Add decompression of Intel's "custom" compression mode (actually LZMA)

Changes:
- Nested firmware volumes are extracted in a hierarchical folder structure
- Compression type 2 (custom) is decompressed using lzmadec

You will need 'lzmadec' on your path.
The code has been reformated by autopep8.

Signed-off-by: James Laird <jhl@mafipulation.org>
Change-Id: I982deb0cc801604225b2056ffed61ffd470fa12b
Reviewed-on: http://review.coreboot.org/1515
Tested-by: build bot (Jenkins)
Reviewed-by: Patrick Georgi <patrick@georgi-clan.de>
1 file changed