vboot2: Add try RO software sync flag

This flag will be used by the firmware updater to indicate that RO
software sync should be attempted.

BUG=chrome-os-partner:48703
BRANCH=None
TEST=make runtests

Change-Id: I42090ac47da45c724e66334648ab447ad3c21178
Signed-off-by: Mary Ruthven <mruthven@chromium.org>
Reviewed-on: https://chromium-review.googlesource.com/320621
Reviewed-by: Randall Spangler <rspangler@chromium.org>
9 files changed