vboot: export offset and type of GBB struct flags member

Export information about vb2_gbb_header's flags member:
  * vb2_gbb_flags_t
  * VB2_GBB_FLAGS_OFFSET

BUG=b:124141368, chromium:954774
TEST=make clean && make runtests
BRANCH=none

Change-Id: I2923156edd06df02751ccded5dcbb5bf8fe0207d
Signed-off-by: Joel Kitching <kitching@google.com>
Reviewed-on: https://chromium-review.googlesource.com/c/chromiumos/platform/vboot_reference/+/1657503
Reviewed-by: Joel Kitching <kitching@chromium.org>
Reviewed-by: Julius Werner <jwerner@chromium.org>
Tested-by: Joel Kitching <kitching@chromium.org>
Commit-Queue: Julius Werner <jwerner@chromium.org>
Auto-Submit: Joel Kitching <kitching@chromium.org>
2 files changed