Btrfs: rename super_kobj to fsid_kobj

Signed-off-by: Anand Jain <anand.jain@oracle.com>
Signed-off-by: David Sterba <dsterba@suse.com>
diff --git a/fs/btrfs/volumes.h b/fs/btrfs/volumes.h
index 2ca784a..413a70c 100644
--- a/fs/btrfs/volumes.h
+++ b/fs/btrfs/volumes.h
@@ -256,7 +256,7 @@
 
 	struct btrfs_fs_info *fs_info;
 	/* sysfs kobjects */
-	struct kobject super_kobj;
+	struct kobject fsid_kobj;
 	struct kobject *device_dir_kobj;
 	struct completion kobj_unregister;
 };