scripts: dtc: make dtb out with alignment 4 bytes

dtb size should be aligned with 4 bytes when we use appended dtb
in the zImage-dtb. Bootloader parses the dtb header from the appended dtb.
If not aligned 4 bytes, it would cause data abort due to unaligned data
access.

Change-Id: I8f80341864ceeb2dddbd23712d8193605c6fb8c3
Signed-off-by: Devin Kim <dojip.kim@lge.com>
ARM: convert build of appended dtb zImage to list of dtbs

Allow CONFIG_BUILD_ARM_APPENDED_DTB_IMAGE_NAMES to specify
a space separated list of dtbs to append to the zImage,
and name the resulting file zImage-dtb

Change-Id: I36d9108a2349bdbb373e95076dcb1417d8c7dce6
Signed-off-by: Colin Cross <ccross@android.com>

Conflicts:
	arch/arm/Kconfig
	arch/arm/Makefile
Signed-off-by: Patrick Tjin <pattjin@google.com>