aufs: outro, module_exit

Although I am not sure module_exit is necessary for the statically
linked module, here is it.  I hope it does no harm.
Signed-off-by: J. R. Okajima <hooanon05g@gmail.com>

fs/aufs/module.c

@@ -241,4 +241,19 @@ out:
 	return err;
 }
 
+static void __exit aufs_exit(void)
+{
+	unregister_filesystem(&aufs_fs_type);
+	au_cache_fin();
+	au_sysrq_fin();
+	au_hnotify_fin();
+	au_loopback_fin();
+	au_wkq_fin();
+	au_procfs_fin();
+	dbgaufs_fin();
+	sysaufs_fin();
+	au_dy_fin();
+}
+
 module_init(aufs_init);
+module_exit(aufs_exit);