LZMA has better compression ratio and is also supported in u-boot already.
ARM BIOS will use LZMA to compress BMP files.
BUG=chromium-os:11017
TEST=manual
$ make
$ make runbmptests
Change-Id: I6b791e3284b65eb3085b0de548bd241eab2ee598
Review URL: http://codereview.chromium.org/6523019