fix(plat/fvp): bump BL2 stack size

VERBOSE print logs need a larger stack size and the currently configured
BL2 stack size was insufficient for FVP. This patch increases the same.

Signed-off-by: Soby Mathew <soby.mathew@arm.com>
Change-Id: I316ba2ea467571161b5f4807e6e5fa0bf89d44c6

plat/arm/board/fvp/include/platform_def.h

@@ -196,7 +196,7 @@
 # if TRUSTED_BOARD_BOOT
 #  define PLATFORM_STACK_SIZE		UL(0x1000)
 # else
-#  define PLATFORM_STACK_SIZE		UL(0x440)
+#  define PLATFORM_STACK_SIZE		UL(0x600)
 # endif
 #elif defined(IMAGE_BL2U)
 # define PLATFORM_STACK_SIZE		UL(0x400)