Input: handle serio_register_driver() errors

Signed-off-by: Akinobu Mita <akinobu.mita@gmail.com>
Signed-off-by: Dmitry Torokhov <dtor@mail.ru>
diff --git a/drivers/input/touchscreen/mtouch.c b/drivers/input/touchscreen/mtouch.c
index c66b399..c3c2d73 100644
--- a/drivers/input/touchscreen/mtouch.c
+++ b/drivers/input/touchscreen/mtouch.c
@@ -208,8 +208,7 @@
 
 static int __init mtouch_init(void)
 {
-	serio_register_driver(&mtouch_drv);
-	return 0;
+	return serio_register_driver(&mtouch_drv);
 }
 
 static void __exit mtouch_exit(void)