Input: alps - use single touch data when v3 mt data contains only one…

… finger

For v3 protocol devices, use the more accurate single touch data when the
mt data contains only one finger. Note the mt data reporting a finger count
of 1 should never happen, but better safe then sorry.

This brings the v3 bitmap handling in line with what the v4 code does,
allowing to factor out the common bits into a helper function.

Signed-off-by: Hans de Goede <hdegoede@redhat.com>
Signed-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>

drivers/input/mouse/alps.c

@@ -669,7 +669,7 @@ static void alps_process_touchpad_packet_v3_v5(struct psmouse *psmouse)
 	 * If we don't have MT data or the bitmaps were empty, we have
 	 * to rely on ST data.
 	 */
-	if (!fingers) {
+	if (fingers < 2) {
 		f->mt[0].x = f->st.x;
 		f->mt[0].y = f->st.y;
 		fingers = f->pressure > 0 ? 1 : 0;