[media] rc: double unlock in rc_register_device()

If change_protocol() fails and we goto out_raw, then it calls unlock
twice.  I noticed that the other time we called change_protocol() we
held the &dev->lock, so I changed it to hold it here too.

Reviewed-by: Jarod Wilson <jarod@redhat.com>
Acked-by: Jarod Wilson <jarod@redhat.com>
Signed-off-by: Dan Carpenter <error27@gmail.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>

drivers/media/rc/rc-main.c

@@ -1099,14 +1099,15 @@ int rc_register_device(struct rc_dev *dev)
 		if (rc < 0)
 			goto out_input;
 	}
-	mutex_unlock(&dev->lock);
 
 	if (dev->change_protocol) {
 		rc = dev->change_protocol(dev, rc_map->rc_type);
 		if (rc < 0)
 			goto out_raw;
 	}
 
+	mutex_unlock(&dev->lock);
+
 	IR_dprintk(1, "Registered rc%ld (driver: %s, remote: %s, mode %s)\n",
 		   dev->devno,
 		   dev->driver_name ? dev->driver_name : "unknown",