fastboot: Add fastboot related flags to vb2

BUG=chrome-os-partner:40196
BRANCH=None
TEST=Compiles successfully.

Change-Id: I4305436b2ae46254e4e8b12039ffed95634d62c2
Signed-off-by: Furquan Shaikh <furquan@google.com>
Reviewed-on: https://chromium-review.googlesource.com/273181
Tested-by: Furquan Shaikh <furquan@chromium.org>
Reviewed-by: Randall Spangler <rspangler@chromium.org>
Commit-Queue: Furquan Shaikh <furquan@chromium.org>
Trybot-Ready: Furquan Shaikh <furquan@chromium.org>
6 files changed