HID: logitech-hidpp: avoid unintended fall-through

Add a return to avoid a fall-through. Introduced in commit
57ac86cf52e903d9e3e0f12b34c814cce6b65550 ("HID: logitech-hidpp: add
support of the first Logitech Wireless Touchpad").

Signed-off-by: Peter Wu <peter@lekensteyn.nl>
Reviewed-by: Benjamin Tissoires <benjamin.tissoires@redhat.com>
Signed-off-by: Jiri Kosina <jkosina@suse.cz>

drivers/hid/hid-logitech-hidpp.c

@@ -805,6 +805,7 @@ static int wtp_raw_event(struct hid_device *hdev, u8 *data, int size)
 			input_event(wd->input, EV_KEY, BTN_RIGHT,
 					!!(data[1] & 0x02));
 			input_sync(wd->input);
+			return 0;
 		} else {
 			if (size < 21)
 				return 1;