Set TARGET_CPU_CORTEX_A53 to enable erratum

This should fix some of the random system and application crashes
that users have been reporting. I'm still not sure we can put this
in common due to the 32bit devices

Change-Id: I0407f1328c73bd806a210df97bae01a746efe0dc

BoardConfig.mk

@@ -21,6 +21,8 @@ TARGET_BOARD_INFO_FILE := $(DEVICE_PATH)/board-info.txt
 
 TARGET_SPECIFIC_HEADER_PATH := $(DEVICE_PATH)/include
 
+TARGET_CPU_CORTEX_A53 := true
+
 # Kernel
 BOARD_KERNEL_TAGS_OFFSET := 0x00000100
 BOARD_RAMDISK_OFFSET     := 0x01000000