doc: Move platform list to the Platform Ports index page

The list of upstream platforms on the index page is growing
quite long, especially with all the FVP variants being listed
individually.

This patch leverages the "Platform Ports" chapter in the docs
table of contents to condense this information. Almost all
platform ports now have documentation, so the table of
contents serves as the list of upstream platforms by itself.

For those upstream platforms that do not have corresponding
documentation, the top-level "Platform Ports" page mentions
them individually. It also mentions each Arm FVP, just as
the index page did before.

Note that there is an in-progress patch that creates new
platform port documentation for the Arm Juno and Arm FVP
platforms, so this list of "other platforms" will soon be
reduced further as those platforms become part of the
table of contents as well.

Change-Id: I6b1eab8cba71a599d85a6e22553a34b07f213268
Signed-off-by: Paul Beesley <paul.beesley@arm.com>
diff --git a/docs/plat/index.rst b/docs/plat/index.rst
index d0b4827..5729635 100644
--- a/docs/plat/index.rst
+++ b/docs/plat/index.rst
@@ -5,6 +5,7 @@
    :maxdepth: 1
    :caption: Contents
    :numbered:
+   :hidden:
 
    allwinner
    meson-gxbb
@@ -35,3 +36,82 @@
    ti-k3
    xilinx-versal
    xilinx-zynqmp
+
+This section provides a list of supported upstream *platform ports* and the
+documentation associated with them. The list of suported Arm |FVP| platforms is
+outlined in the following section.
+
+.. note::
+   In addition to the platforms ports listed within the table of contents, there
+   are several additional platforms that are supported upstream but which do not
+   currently have associated documentation:
+
+   - Arm Juno Software Development Platform. Various |AArch32| and |AArch64|
+     builds of this release have been tested on r0, r1 and r2 variants of the
+     `Juno Arm Development Platform`_.
+   - Arm Neoverse N1 System Development Platform (N1SDP)
+   - Arm Neoverse Reference Design N1 Edge (RD-N1-Edge) FVP
+   - Arm Neoverse Reference Design E1 Edge (RD-E1-Edge) FVP
+   - Arm SGI-575 and SGM-775
+   - MediaTek MT6795 and MT8173 SoCs
+
+Fixed Virtual Platform (FVP) Support
+------------------------------------
+
+The latest version of the AArch64 build of TF-A has been tested on the
+following Arm FVPs without shifted affinities, and that do not support threaded
+CPU cores (64-bit host machine only).
+
+.. note::
+   The FVP models used are Version 11.6 Build 45, unless otherwise stated.
+
+-  ``FVP_Base_AEMv8A-AEMv8A``
+-  ``FVP_Base_AEMv8A-AEMv8A-AEMv8A-AEMv8A-CCN502``
+-  ``FVP_Base_RevC-2xAEMv8A``
+-  ``FVP_Base_Cortex-A32x4``
+-  ``FVP_Base_Cortex-A35x4``
+-  ``FVP_Base_Cortex-A53x4``
+-  ``FVP_Base_Cortex-A55x4+Cortex-A75x4``
+-  ``FVP_Base_Cortex-A55x4``
+-  ``FVP_Base_Cortex-A57x1-A53x1``
+-  ``FVP_Base_Cortex-A57x2-A53x4``
+-  ``FVP_Base_Cortex-A57x4-A53x4``
+-  ``FVP_Base_Cortex-A57x4``
+-  ``FVP_Base_Cortex-A72x4-A53x4``
+-  ``FVP_Base_Cortex-A72x4``
+-  ``FVP_Base_Cortex-A73x4-A53x4``
+-  ``FVP_Base_Cortex-A73x4``
+-  ``FVP_Base_Cortex-A75x4``
+-  ``FVP_Base_Cortex-A76x4``
+-  ``FVP_Base_Cortex-A76AEx4`` (Tested with internal model)
+-  ``FVP_Base_Cortex-A76AEx8`` (Tested with internal model)
+-  ``FVP_Base_Cortex-A77x4`` (Version 11.7 build 36)
+-  ``FVP_Base_Neoverse-N1x4`` (Tested with internal model)
+-  ``FVP_CSS_SGI-575`` (Version 11.3 build 42)
+-  ``FVP_CSS_SGM-775`` (Version 11.3 build 42)
+-  ``FVP_RD_E1Edge`` (Version 11.3 build 42)
+-  ``FVP_RD_N1Edge`` (Version 11.3 build 42)
+-  ``Foundation_Platform``
+
+The latest version of the AArch32 build of TF-A has been tested on the
+following Arm FVPs without shifted affinities, and that do not support threaded
+CPU cores (64-bit host machine only).
+
+-  ``FVP_Base_AEMv8A-AEMv8A``
+-  ``FVP_Base_Cortex-A32x4``
+
+.. note::
+   The ``FVP_Base_RevC-2xAEMv8A`` FVP only supports shifted affinities.
+
+The *Foundation* FVP can be downloaded free of charge. The *Base* FVPs can be
+licensed from Arm. See the `Arm FVP website`_.
+
+All the above platforms have been tested with `Linaro Release 19.06`_.
+
+--------------
+
+*Copyright (c) 2019, Arm Limited. All rights reserved.*
+
+.. _Juno Arm Development Platform: http://www.arm.com/products/tools/development-boards/versatile-express/juno-arm-development-platform.php
+.. _Arm FVP website: https://developer.arm.com/products/system-design/fixed-virtual-platforms
+.. _Linaro Release 19.06: http://releases.linaro.org/members/arm/platforms/19.06