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/penmount.c b/drivers/input/touchscreen/penmount.c
index 6c7d0c2..bd27679 100644
--- a/drivers/input/touchscreen/penmount.c
+++ b/drivers/input/touchscreen/penmount.c
@@ -171,8 +171,7 @@
 
 static int __init pm_init(void)
 {
-	serio_register_driver(&pm_drv);
-	return 0;
+	return serio_register_driver(&pm_drv);
 }
 
 static void __exit pm_exit(void)