Input: wacom_w8001 - set BTN_TOOL_DOUBLETAP if we have 2fg support

BugLink: http://bugs.launchpad.net/bugs/1542771Signed-off-by: Peter Hutterer <peter.hutterer@who-t.net>
Acked-by: Benjamin Tissoires <benjamin.tissoires@gmail.com>
Reviewed-by: Ping Cheng <pingc@wacom.com>
Signed-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>
(cherry picked from commit ec9acda7)
Signed-off-by: Chris J Arges <chris.j.arges@canonical.com>
Signed-off-by: Tim Gardner <tim.gardner@canonical.com>

drivers/input/touchscreen/wacom_w8001.c

@@ -471,6 +471,7 @@ static int w8001_setup(struct w8001 *w8001)
 		case 5:
 			w8001->pktlen = W8001_PKTLEN_TOUCH2FG;
 
+			__set_bit(BTN_TOOL_DOUBLETAP, dev->keybit);
 			input_mt_init_slots(dev, 2, 0);
 			input_set_abs_params(dev, ABS_MT_POSITION_X,
 						0, touch.x, 0, 0);