Revert "Implement kexec-hardboot"

This reverts commit e48d4b15c74d9fe3c62764aee61c472af44ffd00.

Conflicts:
	arch/arm/boot/compressed/head.S
kexec-hardboot: based on @Tasssadar https://github.com/Tasssadar/android_kernel_google_msm/commit/005cf387c1404eac862cc35153d7641d18faef4c