doc: Render Marvell platform documents

The documentation for Marvell platforms was not included in the
rendered document output until now because, while it was mostly
valid RST format, the files were saved with a .txt extension.

This patch corrects some RST formatting errors, creates a document
tree (index page) for the Marvell documents, and adds the Marvell
subtree to the main index.

Change-Id: Id7d4ac37eded636f8f62322a153e1e5f652ff51a
Signed-off-by: Paul Beesley <paul.beesley@arm.com>
diff --git a/docs/plat/marvell/misc/mvebu-a8k-addr-map.rst b/docs/plat/marvell/misc/mvebu-a8k-addr-map.rst
new file mode 100644
index 0000000..e88a458
--- /dev/null
+++ b/docs/plat/marvell/misc/mvebu-a8k-addr-map.rst
@@ -0,0 +1,49 @@
+Address decoding flow and address translation units of Marvell Armada 8K SoC family
+===================================================================================
+
+::
+
+  +--------------------------------------------------------------------------------------------------+
+  |                                                              +-------------+    +--------------+ |
+  |                                                              | Memory      +-----   DRAM CS    | |
+  |+------------+ +-----------+ +-----------+                    | Controller  |    +--------------+ |
+  ||  AP DMA    | |           | |           |                    +-------------+                     |
+  ||  SD/eMMC   | | CA72 CPUs | |  AP MSS   |                    +-------------+                     |
+  ||  MCI-0/1   | |           | |           |                    | Memory      |                     |
+  |+------+-----+ +--+--------+ +--------+--+  +------------+    | Controller  |     +-------------+ |
+  |       |          |                   |     |            +----- Translaton  |     |AP           | |
+  |       |          |                   |     |            |    +-------------+     |Configuration| |
+  |       |          |                   +-----+            +-------------------------Space        | |
+  |       |          | +-------------+         |  CCU       |                        +-------------+ |
+  |       |          | | MMU         +---------+  Windows   |   +-----------+        +-------------+ |
+  |       |          +-| translation |         |  Lookup    +----           +---------   AP SPI    | |
+  |       |            +-------------+         |            |   |           |        +-------------+ |
+  |       |            +-------------+         |            |   |  IO       |        +-------------+ |
+  |       +------------| SMMU        +---------+            |   |  Windows  +---------  AP MCI0/1  | |
+  |                    | translation |         +------------+   |  Lookup   |        +-------------+ |
+  |                    +---------+---+                          |           |        +-------------+ |
+  |             -                |                              |           +---------   AP STM    | |
+  |             +-----------------                              |           |        +-------------+ |
+  | AP          |                |                              +-+---------+                        |
+  +---------------------------------------------------------------|----------------------------------+
+  +-------------|-------------------------------------------------|----------------------------------+
+  | CP          |            +-------------+               +------+-----+      +-------------------+ |
+  |             |            |             |               |            +-------   SB CFG Space    | |
+  |             |            |   DIOB      |               |            |      +-------------------+ |
+  |             |            |   Windows   -----------------  IOB       |      +-------------------+ |
+  |             |            |   Control   |               |  Windows   +------| SB PCIe-0 - PCIe2 | |
+  |             |            |             |               |  Lookup    |      +-------------------+ |
+  |             |            +------+------+               |            |      +-------------------+ |
+  |             |                   |                      |            +------+      SB NAND      | |
+  |             |                   |                      +------+-----+      +-------------------+ |
+  |             |                   |                             |                                  |
+  |             |                   |                             |                                  |
+  |   +------------------+   +------------+                +------+-----+      +-------------------+ |
+  |   | Network Engine   |   |            |                |            +-------  SB SPI-0/SPI-1   | |
+  |   | Security Engine  |   | PCIe, MSS  |                |  RUNIT     |      +-------------------+ |
+  |   | SATA, USB        |   | DMA        |                |  Windows   |      +-------------------+ |
+  |   | SD/eMMC          |   |            |                |  Lookup    +-------   SB Device Bus   | |
+  |   | TDM, I2C         |   |            |                |            |      +-------------------+ |
+  |   +------------------+   +------------+                +------------+                            |
+  |                                                                                                  |
+  +--------------------------------------------------------------------------------------------------+