The two I2C commands for battery cut-off must be sent out back to back.
Thus we need to guard them with I2C port lock to prevent being
preempted.
BUG=chrome-os-partner:19901
TEST=Check battery cutoff still works.
BRANCH=spring
Change-Id: Iac51037432b108d4cac29d5c73cafa9ce2310b12
Signed-off-by: Vic Yang <victoryang@chromium.org>
Reviewed-on: https://gerrit.chromium.org/gerrit/57598
Reviewed-by: Vincent Palatin <vpalatin@chromium.org>
Reviewed-by: Randall Spangler <rspangler@chromium.org>