Add Ctrl-Enter as an additional key to trigger dev USB boot.

Due to the limitation of servo that is unable to send U keys, dev USB boot
(triggered by Ctrl-U) is unable to be tested on FAFT. To solve it, firmware
should add an addition key combination to workaround it. Ctrl-Enter is the
one we picked.

BUG=chrome-os-partner:6759
TEST=compile the firmware and update it to Lumpy; during the dev screen,
press Ctrl-Enter to trigger USB boot.

Reviewed-on: https://gerrit.chromium.org/gerrit/15749
Reviewed-by: Randall Spangler <rspangler@chromium.org>
Commit-Ready: Tom Wai-Hong Tam <waihong@chromium.org>
Tested-by: Tom Wai-Hong Tam <waihong@chromium.org>

(cherry picked from commit 2ddd5f64515b4be9847a16de793c59b161221e1b)

Change-Id: Ib10e29864c95c8a6fb417d5530bcea599699357f
Reviewed-on: https://gerrit.chromium.org/gerrit/15917
Tested-by: Stefan Reinauer <reinauer@google.com>
Reviewed-by: Randall Spangler <rspangler@chromium.org>
2 files changed