input: lis302: disable KEY_* input events

Those KEY events are recognized as button press in Android/Replicant and
thus acquire a wakelock of 5 sec. This happens several times per second,
which leads to the situation that the device will never suspend or dim
its screen on its own. Therefore we need to disable those events.

Signed-off-by: Lukas Märdian <lukas@goldelico.com>