Commit 
d1cf5788450e ("rbd: set mapping info earlier") defined
rbd_dev_mapping_clear(), but, just a few days after, commit
f35a4dee14c3 ("rbd: set the mapping size and features later") moved
rbd_dev_mapping_set() calls and added another rbd_dev_mapping_clear()
call instead of moving the old one.  Around the same time, another
duplicate was introduced in rbd_dev_device_release() - kill both.
Signed-off-by: Ilya Dryomov <idryomov@gmail.com>
                unregister_blkdev(rbd_dev->major, rbd_dev->name);
 err_out_id:
        rbd_dev_id_put(rbd_dev);
-       rbd_dev_mapping_clear(rbd_dev);
-
        return ret;
 }
 
        if (!single_major)
                unregister_blkdev(rbd_dev->major, rbd_dev->name);
        rbd_dev_id_put(rbd_dev);
-       rbd_dev_mapping_clear(rbd_dev);
 }
 
 static void rbd_dev_remove_parent(struct rbd_device *rbd_dev)