RDMA/mlx5: Return proper value for not-supported command

Return -EOPNOTSUPP value to the user for unsupported reg_user_mr.
Signed-off-by: NLeon Romanovsky <leonro@mellanox.com>
Signed-off-by: NDoug Ledford <dledford@redhat.com>

drivers/infiniband/hw/mlx5/mr.c

@@ -1220,7 +1220,7 @@ struct ib_mr *mlx5_ib_reg_user_mr(struct ib_pd *pd, u64 start, u64 length,
 	bool use_umr = true;
 
 	if (!IS_ENABLED(CONFIG_INFINIBAND_USER_MEM))
-		return ERR_PTR(-EINVAL);
+		return ERR_PTR(-EOPNOTSUPP);
 
 	mlx5_ib_dbg(dev, "start 0x%llx, virt_addr 0x%llx, length 0x%llx, access_flags 0x%x\n",
 		    start, virt_addr, length, access_flags);