recovery: Add recovery reason for fastboot mode requested in fw

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

Change-Id: Ic69834f2e23926e618349b5a56db549a290cd0c2
Signed-off-by: Furquan Shaikh <furquan@google.com>
Reviewed-on: https://chromium-review.googlesource.com/280922
Trybot-Ready: Furquan Shaikh <furquan@chromium.org>
Tested-by: Furquan Shaikh <furquan@chromium.org>
Reviewed-by: Randall Spangler <rspangler@chromium.org>
Commit-Queue: Furquan Shaikh <furquan@chromium.org>
3 files changed