NFS: sysfs: fix leak when nfs_client kobject add fails

If adding the second kobject fails, drop both references to avoid sysfs
residue and memory leak.

Fixes: e96f9268ee ("NFS: Make all of /sys/fs/nfs network-namespace unique")

Signed-off-by: Yang Xiuwei <yangxiuwei@kylinos.cn>
Reviewed-by: Benjamin Coddington <ben.coddington@hammerspace.com>
Signed-off-by: Anna Schumaker <anna.schumaker@oracle.com>

fs/nfs/sysfs.c

@@ -189,6 +189,7 @@ static struct nfs_netns_client *nfs_netns_client_alloc(struct kobject *parent,
 			return p;
 
 		kobject_put(&p->kobject);
+		kobject_put(&p->nfs_net_kobj);
 	}
 	return NULL;
 }