vboot: GPT interface cleanup

- Rename drive_sectors to streaming_drive_sectors, to contrast with
  gpt_drive_sectors
- Replace stored_on_device field with flags field for future
  extensibility

BUG=chromium:433433
TEST=make runtests
BRANCH=none

Change-Id: I785a3b735b8eb96f647a334659329db3ee43eb80
Signed-off-by: Dan Ehrenberg <dehrenberg@chromium.org>
Reviewed-on: https://chromium-review.googlesource.com/234283
Reviewed-by: Bill Richardson <wfrichar@chromium.org>
10 files changed