RDMA/core: Fix a WARN() message

The first parameter of WARN_ONCE() is a condition, then following
parameters are the message.  In this case, we left out the condition so it
will just print the ops->type string.

Fixes: 3856ec4b93 ("RDMA/core: Add RDMA_NLDEV_CMD_NEWLINK/DELLINK support")
Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
Reviewed-by: Majd Dibbiny <majd@mellanox.com>
Reviewed-by: Steve Wise <swise@opengridcomputing.com>
Signed-off-by: Jason Gunthorpe <jgg@mellanox.com>

drivers/infiniband/core/nldev.c

@@ -1222,10 +1222,8 @@ out:
 void rdma_link_register(struct rdma_link_ops *ops)
 {
 	down_write(&link_ops_rwsem);
-	if (link_ops_get(ops->type)) {
-		WARN_ONCE("Duplicate rdma_link_ops! %s\n", ops->type);
+	if (WARN_ON_ONCE(link_ops_get(ops->type)))
 		goto out;
-	}
 	list_add(&ops->list, &link_ops);
 out:
 	up_write(&link_ops_rwsem);