HID: sony: Expose DS3 motion sensors through separate device

This patch adds a separate evdev node for the DS3 its motion
sensors. We only expose the accelerometers as the gyroscope
is extremely difficult to manage and behavior varies a lot
between hardware revisions.

Signed-off-by: Roderick Colenbrander <roderick.colenbrander@sony.com>
Signed-off-by: Jiri Kosina <jkosina@suse.cz>