RDMA/mlx5: Use correct device num_ports when modify DC

Just like other QP types, when modify DC, the port_num should be compared
with dev->num_ports, instead of HCA_CAP.num_ports.  Otherwise Multi-port
vHCA on DC may not work.

Fixes: 776a390 ("IB/mlx5: Add support for DC target QP")
Link: https://lore.kernel.org/r/20230420013906.1244185-1-markzhang@nvidia.com
Signed-off-by: Mark Zhang <markzhang@nvidia.com>
Reviewed-by: Maor Gottlieb <maorg@nvidia.com>
Signed-off-by: Jason Gunthorpe <jgg@nvidia.com>

drivers/infiniband/hw/mlx5/qp.c

@@ -4493,7 +4493,7 @@ static int mlx5_ib_modify_dct(struct ib_qp *ibqp, struct ib_qp_attr *attr,
 			return -EINVAL;
 
 		if (attr->port_num == 0 ||
-		    attr->port_num > MLX5_CAP_GEN(dev->mdev, num_ports)) {
+		    attr->port_num > dev->num_ports) {
 			mlx5_ib_dbg(dev, "invalid port number %d. number of ports is %d\n",
 				    attr->port_num, dev->num_ports);
 			return -EINVAL;