lib: Add support for LZ4-compressed kernel

This patch adds support for extracting LZ4-compressed kernel images,
as well as LZ4-compressed ramdisk images in the kernel boot process.

This depends on the patch below
decompressor: Add LZ4 decompressor module

Signed-off-by: Kyungsik Lee <kyungsik.lee@lge.com>

v2:
- Clean up code
- Use lz4_decompress() for LZ4-compressed kernel during boot-process
v3:
- Use an inline function instead of macro to prevent double evaluation
- Add LZ4 description and note for uncompressed chunk size

Change-Id: If4164b492a9694f37270e7d0f602e6f46a3fd62e
arm: Add support for LZ4-compressed kernel

This patch integrates the LZ4 decompression code to the arm pre-boot code.
And it depends on two patchs below

lib: Add support for LZ4-compressed kernel
decompressor: Add LZ4 decompressor module

Signed-off-by: Kyungsik Lee <kyungsik.lee@lge.com>

v2:
- Apply CFLAGS, -Os to decompress.o to improve decompress
  performance during boot-up process
ARM: 7583/1: decompressor: Enable unaligned memory access for v6 and above

Modern GCC can generate code which makes use of the CPU's native
unaligned memory access capabilities.  This is useful for the C
decompressor implementations used for unpacking compressed kernels.

This patch disables alignment faults and enables the v6 unaligned
access model on CPUs which support these features (i.e., v6 and
later), allowing full unaligned access support for C code in the
decompressor.

The decompressor C code must not be built to assume that unaligned
access works if support for v5 or older platforms is included in
the kernel.

For correct code generation, C decompressor code must always use
the get_unaligned and put_unaligned accessors when dealing with
unaligned pointers, regardless of this patch.

Signed-off-by: Dave Martin <dave.martin@linaro.org>
Acked-by: Nicolas Pitre <nico@linaro.org>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
defconfigs: use LZ4 compression for kernel & ramdisk

http://events.linuxfoundation.org/sites/events/files/lcjpcojp13_klee.pdf

Signed-off-by: Michael Bestas <mikeioannina@gmail.com>

Change-Id: I1e9bcdafb637fefcccfba2a6c870ac3cdee7ae5b
lz4: update executable name

newer revisions are named lz4c instead of lz4demo

Signed-off-by: Michael Bestas <mikeioannina@gmail.com>

Change-Id: I213143efcf7a71fcc7240a48505c73deebdd48a3