xen/blkfront: add __exit to module_exit() handlers

Signed-off-by: Jan Beulich <jbeulich@novell.com>
Signed-off-by: Jeremy Fitzhardinge <jeremy.fitzhardinge@citrix.com>
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
diff --git a/drivers/block/xen-blkfront.c b/drivers/block/xen-blkfront.c
index a39b4b2..b00682e 100644
--- a/drivers/block/xen-blkfront.c
+++ b/drivers/block/xen-blkfront.c
@@ -1045,7 +1045,7 @@
 module_init(xlblk_init);
 
 
-static void xlblk_exit(void)
+static void __exit xlblk_exit(void)
 {
 	return xenbus_unregister_driver(&blkfront);
 }