Veyron minnie embedded controller presents 2 accelerometers using an
older interface. Add function to query the data in cros_ec_accel.

Verify accelerometers on veyron-minnie are presented and working.
Signed-off-by: Gwendal Grignou <gwendal@chromium.org>
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>