MSM: add keyboard driver in st1.5

BUG=NONE
TEST=Built and ran on st1.5

Signed-off-by: Horace Fu <horace.fu@quantatw.com>
Signed-off-by: Mandeep Singh Baines <msb@chromium.org>

Review URL: http://codereview.chromium.org/723001



Change-Id: Ib7db8eb5c4c2fe3a8e957cb917ebad05f1ee3f1f
Signed-off-by: Ajay Dudani <adudani@codeaurora.org>