HID: sony: add output events for the multi-touch pad on the Dualshock 4

Add output events for the multi-touch pad on the Dualshock 4.

The touchpad has a resolution of 1920x940 and is capable of 2 simultaneous
touches. A 'Type B' stateful slot protocol is implemented as defined in
Documentation/input/multi-touch-protocol.txt

Applications can use the touchpad data by processing the ABS_MT_SLOT,
ABS_MT_TRACKING_ID, ABS_MT_POSITION_X and ABS_MT_POSITION_Y events.

Signed-off-by: Frank Praznik <frank.praznik@oh.rr.com>
Signed-off-by: Jiri Kosina <jkosina@suse.cz>