Allow Device specific ramdisk address

Change-Id: If0bb3d3a2b51f87a92c0b657fbc6d0277ce53532

Conflicts:
	core/Makefile
Deprecate BOARD_FORCE_RAMDISK_ADDRESS in favor of BOARD_MKBOOTIMG_ARGS.

Change-Id: Ib587f14cb45d752356beec3998a5b956f8b09efa