cros_bundle_firmware: Add post-process script support

Add option to run post-process script on an image. For smaug board,
call script nv_pkc_signing.sh with required arguments.

CQ-DEPEND=CL:290473
BUG=chrome-os-partner:43572
BRANCH=None
TEST=emerge-smaug chromeos-bootimage generates properly signed images.

Change-Id: Idbfea8c15bf15c90a106b7c99680915eea111143
Signed-off-by: Furquan Shaikh <furquan@google.com>
Reviewed-on: https://chromium-review.googlesource.com/290435
Trybot-Ready: Furquan Shaikh <furquan@chromium.org>
Tested-by: Furquan Shaikh <furquan@chromium.org>
Reviewed-by: Stefan Reinauer <reinauer@chromium.org>
Commit-Queue: Furquan Shaikh <furquan@chromium.org>
1 file changed