This patch adds support for the CBFS attributes that were already
introduced in cbfstool and libpayload. I'm only copy&pasting the header
definitions needed for this once more. Really, we should be unifying the
definitions (and possibly part of the code) from cbfstool with
commonlib, but apparently that hadn't been done when this feature was
introduced and I don't really have time to do it cleanly now.

Also add a function to extract info from the compression attribute,
which can then be used to run cbfs_load_and_decompress() on the file.

Change-Id: I7b6463597757122cfe84f006c946a1658bb3acc6
Signed-off-by: Julius Werner <jwerner@chromium.org>
Reviewed-on: https://review.coreboot.org/16271


Tested-by: build bot (Jenkins)
Reviewed-by: Aaron Durbin <adurbin@chromium.org>