[media] media: rc: remove unneeded mutex in rc_register_device

Access to dev->initialized is atomic and dev->initialized isn't
accessed in any other code protected by this mutex.
Therefore we don't need to get the mutex here.
Signed-off-by: Heiner Kallweit <hkallweit1@gmail.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@osg.samsung.com>

drivers/media/rc/rc-main.c

@@ -1492,9 +1492,7 @@ int rc_register_device(struct rc_dev *dev)
 	}
 
 	/* Allow the RC sysfs nodes to be accessible */
-	mutex_lock(&dev->lock);
 	atomic_set(&dev->initialized, 1);
-	mutex_unlock(&dev->lock);
 
 	IR_dprintk(1, "Registered rc%u (driver: %s, remote: %s, mode %s)\n",
 		   dev->minor,