arm: add support for LZ4-compressed kernel

Integrates the LZ4 decompression code to the arm pre-boot code.

Signed-off-by: Kyungsik Lee <kyungsik.lee@lge.com>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Russell King <rmk@arm.linux.org.uk>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Florian Fainelli <florian@openwrt.org>
Cc: Yann Collet <yann.collet.73@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

Conflicts:
	arch/arm/Kconfig
	arch/arm/boot/compressed/Makefile
	arch/x86/boot/compressed/Makefile

Change-Id: Ie4712fba77e3cc30ce7a11eee7bd29a8f8f58468

Conflicts:
	arch/arm/boot/compressed/Makefile