asus-laptop: Pegatron Lucid accelerometer

Support the built-in accelerometer on the Lucid tablets as a standard
3-axis input device.

Signed-off-by: Andy Ross <andy.ross@windriver.com>
Signed-off-by: Corentin Chary <corentin.chary@gmail.com>
Signed-off-by: Matthew Garrett <mjg@redhat.com>