features->quirks can have multiple bits set. For dual input, we only
need to check WACOM_QUIRK_MULTI_INPUT.
Reviewed-by: NJason Gerecke <killertofu@gmail.com>
Signed-off-by: NPing Cheng <pingc@wacom.com>
Signed-off-by: NDmitry Torokhov <dmitry.torokhov@gmail.com>