cros_bundle_firmware: allow building GBBs without bitmaps

Embedded chrome OS targets might not require bitmaps in the GBB, it is
useful to be able to build a bootimage without requiring bitmaps.

This patch adds an option (--skip-bmpblk), which makes sure that
futility is invoked in a manner not requiring inclusion of the bitmap.

BUG=chrome-os-partner:31438
TEST=ran 'cros_bundle_firmware' with options requiring and skipping
     bitmap, both cases resulted in a valid firmware image

Change-Id: I3e109b4d256dd16e1f26597ee8c0caee26d2d098
Signed-off-by: Vadim Bendebury <vbendeb@chromium.org>
Reviewed-on: https://chromium-review.googlesource.com/232045
Reviewed-by: Bill Richardson <wfrichar@chromium.org>
Reviewed-on: https://chromium-review.googlesource.com/236113
2 files changed