Input: wacom - handle Intuos 4 BT in wacom.ko

A good point of this change is that now, the Intuos4 bluetooth can handle
the different tools (artpen, airbrush, mice), and we get a common interface
between USB and BT for accessing the LEDs/OLEDs.

Signed-off-by: Benjamin Tissoires <benjamin.tissoires@redhat.com>
Reviewed-by: Ping Cheng <pingc@wacom.com>
Tested-by: Przemo Firszt <przemo@firszt.eu>
Signed-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>