faft: Speed up the waiting time for dev screen and sync

Waiting for a dev screen and pressing Ctrl-D is a recurrent action.
Booting to a dev screen is a bit faster than other firmware screens,
like recovery insert screen. We can make the dev screen a separated
case from other firmware screens for speed-up. It can save 3 seconds
each time.

Also the sync delay can be faster, from 5 seconds to 2 seconds.

BUG=chromium-os:34392
TEST=run FAFT suite on Link and the dev screen timing is correct.

Change-Id: I377494cc44b4bb9ca3e2d2addee3cb34a2d511d0
Reviewed-on: https://gerrit.chromium.org/gerrit/38630
Reviewed-by: Vic Yang <victoryang@chromium.org>
Commit-Ready: Tom Wai-Hong Tam <waihong@chromium.org>
Tested-by: Tom Wai-Hong Tam <waihong@chromium.org>
4 files changed