xen/blkfront: add __exit to module_exit() handlers

Signed-off-by: NJan Beulich <jbeulich@novell.com>
Signed-off-by: NJeremy Fitzhardinge <jeremy.fitzhardinge@citrix.com>
Signed-off-by: NJens Axboe <jens.axboe@oracle.com>

drivers/block/xen-blkfront.c

@@ -1045,7 +1045,7 @@ static int __init xlblk_init(void)
 module_init(xlblk_init);
 
 
-static void xlblk_exit(void)
+static void __exit xlblk_exit(void)
 {
 	return xenbus_unregister_driver(&blkfront);
 }