plat: marvell: armada: a3k: Add a new target mrvl_uart which builds UART image

This change separates building of flash and UART images, so it is possible
to build only one of these images. Also this change allows make to build
them in parallel.

Target mrvl_flash now builds only flash image and mrvl_uart only UART
image. This change reflects it also in the documentation.

Signed-off-by: Pali Rohár <pali@kernel.org>
Change-Id: Ie9ce4538d52188dd26d99dfeeb5ad171a5b818f3
diff --git a/docs/plat/marvell/armada/build.rst b/docs/plat/marvell/armada/build.rst
index d224779..750bf66 100644
--- a/docs/plat/marvell/armada/build.rst
+++ b/docs/plat/marvell/armada/build.rst
@@ -236,7 +236,7 @@
         MARVELL_SECURE_BOOT=0 DDR_TOPOLOGY=3 BOOTDEV=SPINOR PARTNUM=0 PLAT=a3700 \
         MV_DDR_PATH=/path/to/mv-ddr-marvell/ WTP=/path/to/A3700-utils-marvell/ \
         CRYPTOPP_PATH=/path/to/cryptopp/ BL33=/path/to/u-boot.bin \
-        all fip mrvl_bootimage mrvl_flash
+        all fip mrvl_bootimage mrvl_flash mrvl_uart
 
 To build just TF-A without WTMI image (useful for A3720 Turris MOX board), run following command:
 
@@ -298,8 +298,9 @@
       for booting via UART. Could be loaded via Marvell's WtpDownload tool from
       A3700-utils-marvell repository.
 
-Additional make target ``mrvl_bootimage`` produce ``boot-image.bin`` file and target
-``mrvl_flash`` produce final ``flash-image.bin`` and ``uart-images.tgz.bin`` files.
+Additional make target ``mrvl_bootimage`` produce ``boot-image.bin`` file. Target
+``mrvl_flash`` produce final ``flash-image.bin`` file and target ``mrvl_uart``
+produce ``uart-images.tgz.bin`` file.
 
 
 Tools and external components installation