Add support for XZ compressed kernel

Change-Id: I42b2912b83d7af374497785820182e8b5e61d12a
Signed-off-by: olivieer <y.karasangabo@bg-rams.ac.at>

Conflicts:
	arch/arm/boot/compressed/.gitignore
	arch/arm/boot/compressed/Makefile
	arch/arm/boot/compressed/decompress.c
	arch/arm/boot/compressed/piggy.bzip2.S
	arch/arm/mm/Makefile
	drivers/regulator/core.c
general: fixup

Signed-off-by: olivieer <y.karasangabo@bg-rams.ac.at>