HID: wacom: Send BTN_TOUCH in response to INTUOSP2_BT eraser contact

The Bluetooth reports from the 2nd-gen Intuos Pro have separate bits for
indicating if the tip or eraser is in contact with the tablet. At the
moment, only the tip contact bit controls the state of the BTN_TOUCH
event. This prevents the eraser from working as expected. This commit
changes the driver to send BTN_TOUCH whenever either the tip or eraser
contact bit is set.

Fixes: 4922cd2 ("HID: wacom: Support 2nd-gen Intuos Pro's Bluetooth classic interface")
Cc: <stable@vger.kernel.org> # 4.11+
Signed-off-by: Jason Gerecke <jason.gerecke@wacom.com>
Reviewed-by: Aaron Skomra <aaron.skomra@wacom.com>
Signed-off-by: Benjamin Tissoires <benjamin.tissoires@redhat.com>

drivers/hid/wacom_wac.c

@@ -1301,7 +1301,7 @@ static void wacom_intuos_pro2_bt_pen(struct wacom_wac *wacom)
 						 range ? frame[7] : wacom->features.distance_max);
 			}
 
-			input_report_key(pen_input, BTN_TOUCH, frame[0] & 0x01);
+			input_report_key(pen_input, BTN_TOUCH, frame[0] & 0x09);
 			input_report_key(pen_input, BTN_STYLUS, frame[0] & 0x02);
 			input_report_key(pen_input, BTN_STYLUS2, frame[0] & 0x04);