smdk4412: add xz compression support

fix compile on smdk4412 kernel and enable in defconfig

From: "Imre Kaloz" <kaloz@openwrt.org>
Subject: Wire up support for the XZ decompressor

Wire up support for the XZ decompressor

Signed-off-by: Imre Kaloz <kaloz@openwrt.org>
Signed-off-by: Humberto Borba <humberos@gmail.com>
Change-Id: I86d7cfa26edc433291ba5e9372b20e65e95fc970
ARM: zImage: ensure it is always a multiple of 64 bits in size

This is needed for proper alignment when the DTB appending feature
is used.

Signed-off-by: Nicolas Pitre <nicolas.pitre@linaro.org>
Acked-by: Tony Lindgren <tony@atomide.com>
Tested-by: Shawn Guo <shawn.guo@linaro.org>
Tested-by: Dave Martin <dave.martin@linaro.org>
Tested-by: Thomas Abraham <thomas.abraham@linaro.org>
Tested-by: David Brown <davidb@codeaurora.org>

Conflicts:

	arch/arm/boot/compressed/vmlinux.lds.in
ARM: zImage: gather some string functions into string.c

This is a small subset of string functions needed by commits to come.
Except for memcpy() which is unchanged from its original location, their
implementation is meant to be small, and -Os is enforced to prevent gcc
from doing pointless loop unrolling.

Signed-off-by: Nicolas Pitre <nicolas.pitre@linaro.org>
Tested-by: Shawn Guo <shawn.guo@linaro.org>
Tested-by: Dave Martin <dave.martin@linaro.org>
Tested-by: Thomas Abraham <thomas.abraham@linaro.org>
Tested-by: David Brown <davidb@codeaurora.org>