mlx4_en: Fix BQL reset TX queue call point

Fix issue in Mellanox driver related to BQL.  netdev_tx_reset_queue
was not being called in certain situations where the device was
being start and stopped.  Moved netdev_tx_reset_queue from the reset
device path to mlx4_en_free_tx_buf which is where the rings are
cleaned in a reset (specifically from device being stopped).
Signed-off-by: Tom Herbert <therbert@google.com>
Acked-By: Amir Vadai <amirv@mellanox.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

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

@@ -1685,15 +1685,12 @@ static void mlx4_en_restart(struct work_struct *work)
 						 watchdog_task);
 	struct mlx4_en_dev *mdev = priv->mdev;
 	struct net_device *dev = priv->dev;
-	int i;
 
 	en_dbg(DRV, priv, "Watchdog task called for port %d\n", priv->port);
 
 	mutex_lock(&mdev->state_lock);
 	if (priv->port_up) {
 		mlx4_en_stop_port(dev, 1);
-		for (i = 0; i < priv->tx_ring_num; i++)
-			netdev_tx_reset_queue(priv->tx_ring[i].tx_queue);
 		if (mlx4_en_start_port(dev))
 			en_err(priv, "Failed restarting port %d\n", priv->port);
 	}

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

@@ -294,6 +294,8 @@ int mlx4_en_free_tx_buf(struct net_device *dev, struct mlx4_en_tx_ring *ring)
 		cnt++;
 	}
 
+	netdev_tx_reset_queue(ring->tx_queue);
+
 	if (cnt)
 		en_dbg(DRV, priv, "Freed %d uncompleted tx descriptors\n", cnt);