mlx4_en: nullify cq->vector field when closing completion queue

Caused loss of connectivity when changing ring size.
Signed-off-by: NYevgeny Petrilin <yevgenyp@mellanox.co.il>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

drivers/net/ethernet/mellanox/mlx4/en_cq.c

@@ -147,6 +147,7 @@ void mlx4_en_destroy_cq(struct mlx4_en_priv *priv, struct mlx4_en_cq *cq)
 	mlx4_free_hwq_res(mdev->dev, &cq->wqres, cq->buf_size);
 	if (priv->mdev->dev->caps.comp_pool && cq->vector)
 		mlx4_release_eq(priv->mdev->dev, cq->vector);
+	cq->vector = 0;
 	cq->buf_size = 0;
 	cq->buf = NULL;
 }