Input: elantech - enable middle button support on 2 ThinkPads

Adding 2 new touchpad PNPIDs to enable middle button support.
Signed-off-by: Aaron Ma <aaron.ma@canonical.com>
Signed-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>

drivers/input/mouse/elantech.c

@@ -1189,6 +1189,8 @@ static const char * const middle_button_pnp_ids[] = {
 	"LEN2132", /* ThinkPad P52 */
 	"LEN2133", /* ThinkPad P72 w/ NFC */
 	"LEN2134", /* ThinkPad P72 */
+	"LEN0407",
+	"LEN0408",
 	NULL
 };