This adds support for Pen on Bamboo Pen and Bamboo Pen&Touch devices.
Touchpad is handled by previous Bamboo Touch logic.
Signed-off-by: NChris Bagwell <chris@cnpbagwell.com>
Acked-by: NPing Cheng <pingc@wacom.com>
Signed-off-by: NDmitry Torokhov <dtor@mail.ru>