[Whale] Driver to emulate keyboard scan

BUG=chrome-os-partner:29166
TEST=Verify on Larvae board

Usage:
  ./bft_fixture.py --config whale/bft.conf SimulateKeystrokes
  ./bft_fixture.py --config whale/bft.conf SimulateKeyPress [bitmask] [period_secs]

Example:
  ./bft_fixture.py --config whale/bft.conf SimulateKeystrokes
  ./bft_fixture.py --config whale/bft.conf SimulateKeyPress 0x8000 3

Change-Id: Ib5e6edc98b631a68d442e55bd1733eff4ade66a1
Reviewed-on: https://chromium-review.googlesource.com/207500
Reviewed-by: Justin Chuang <jchuang@chromium.org>
Tested-by: Aaron Chuang <aaron.chuang@quantatw.com>
Commit-Queue: Aaron Chuang <aaron.chuang@quantatw.com>
3 files changed