firmware_FAFTSetup: Check EC console availability

This checks EC console is not attached by other process. Also minor
improvement on keyboard simulation check.

BUG=chrome-os-partner:13811
TEST=Test passed. Connect EC console with minicom, and check test
fails.

Change-Id: Ie686fe99dacaac9b7a18a0739a4ba28f9be62110
Reviewed-on: https://gerrit.chromium.org/gerrit/33171
Reviewed-by: Tom Wai-Hong Tam <waihong@chromium.org>
Commit-Ready: Vic Yang <victoryang@chromium.org>
Tested-by: Vic Yang <victoryang@chromium.org>
1 file changed