Add a missing unlock_kernel() in raw_open()

Cc: stable@kernel.org
Signed-off-by: Dan Carpenter <error27@gmail.com>
Signed-off-by: Jonathan Corbet <corbet@lwn.net>

drivers/char/raw.c

@@ -90,6 +90,7 @@ static int raw_open(struct inode *inode, struct file *filp)
 	blkdev_put(bdev, filp->f_mode);
 out:
 	mutex_unlock(&raw_mutex);
+	unlock_kernel();
 	return err;
 }