Add kexec-hardboot support for MultiROM

Change-Id: I1183ff51ef583b8f8b1f96ebfb668c67e26f6b8e

Conflicts:
	arch/arm/configs/cm_m8_defconfig
	arch/arm/include/asm/kexec.h
	arch/arm/kernel/machine_kexec.c
	arch/arm/mach-msm/restart.c
	include/linux/kexec.h