futility: update: Add '--gbb_flags FLAGS' to override GBB flags

Developers may want to use the new GBB flags when flashing a firmware
image. That can be done by --factory, but it's also more convenient to
have a new parameter for overriding the flags with a new value.

BRANCH=none
BUG=b:166569397
TEST=make runtests

Change-Id: If9dce9b1f2fbb27655ad2a111ba75ab83375fb7a
Signed-off-by: Hung-Te Lin <hungte@chromium.org>
Reviewed-on: https://chromium-review.googlesource.com/c/chromiumos/platform/vboot_reference/+/2382991
Reviewed-by: Julius Werner <jwerner@chromium.org>
4 files changed