Adds the Dualshock 4 to the HID device list and enables force-feedback.

Adds a Dualshock 4 specific worker function since the Dualshock 4 needs a
different report than the Sixaxis.

The right motor in the Dualshock 4 is variable so the full rumble value
is now passed to the worker function and clamped there if necessary.
Signed-off-by: Frank Praznik <frank.praznik@oh.rr.com>
Signed-off-by: Jiri Kosina <jkosina@suse.cz>