HID: wacom: Recognize new MobileStudio Pro PID

A new PID is in use for repaired MobileStudio Pro devices. Add it to the
list of devices that need special-casing in wacom_wac_pad_event.

Signed-off-by: Jason Gerecke <jason.gerecke@wacom.com>
Signed-off-by: Benjamin Tissoires <benjamin.tissoires@redhat.com>