add battery driver in st1.5

BUG=NONE
TEST=Built and ran on st1.5
Signed-off-by: Horace Fu <horace.fu@quantatw.com>

Review URL: http://codereview.chromium.org/1637005


(cherry picked from commit 2fffb8921503d2fc3a1d7ecf5e52c8512bfd9b18)

Signed-off-by: Benson Leung <bleung@chromium.org>

Review URL: http://codereview.chromium.org/2850001



Change-Id: Ic43ec80dbf9b3c682f1a3742f543781550f86436
Signed-off-by: Neil Leeder <nleeder@codeaurora.org>