ddr: a80x0: add DDR 32-bit mode support

This commit introduces 32-bit DDR topology map initialization.
For that purpose a new DDR32 build flag is added, with
according documentation update.

Change-Id: I169ff358c2923afd984e27bc126dc551dcaefc01
Signed-off-by: Alex Leibovich <alexl@marvell.com>
diff --git a/plat/marvell/marvell.mk b/plat/marvell/marvell.mk
index d8be0dd..8245753 100644
--- a/plat/marvell/marvell.mk
+++ b/plat/marvell/marvell.mk
@@ -16,6 +16,10 @@
 PALLADIUM			:= 0
 $(eval $(call add_define,PALLADIUM))
 
+# Set board to work with DDR 32bit
+DDR32				:= 0
+$(eval $(call add_define,DDR32))
+
 ifeq (${MARVELL_SECURE_BOOT},1)
 DOIMAGE_SEC_FLAGS := -c $(DOIMAGE_SEC)
 DOIMAGE_LIBS_CHECK = \