net: ethernet: altera: TSE: Remove unneeded dma sync for tx buffers

An explicit dma sync for device directly after mapping as well as an
explicit dma sync for cpu directly before unmapping is unnecessary and
costly on the hotpath. So remove these calls.

Signed-off-by: Lino Sanfilippo <LinoSanfilippo@gmx.de>
Signed-off-by: David S. Miller <davem@davemloft.net>

drivers/net/ethernet/altera/altera_tse_main.c

@@ -400,12 +400,6 @@ static int tse_rx(struct altera_tse_private *priv, int limit)
 
 		skb_put(skb, pktlength);
 
-		/* make cache consistent with receive packet buffer */
-		dma_sync_single_for_cpu(priv->device,
-					priv->rx_ring[entry].dma_addr,
-					priv->rx_ring[entry].len,
-					DMA_FROM_DEVICE);
-
 		dma_unmap_single(priv->device, priv->rx_ring[entry].dma_addr,
 				 priv->rx_ring[entry].len, DMA_FROM_DEVICE);
 
@@ -592,10 +586,6 @@ static int tse_start_xmit(struct sk_buff *skb, struct net_device *dev)
 	buffer->dma_addr = dma_addr;
 	buffer->len = nopaged_len;
 
-	/* Push data out of the cache hierarchy into main memory */
-	dma_sync_single_for_device(priv->device, buffer->dma_addr,
-				   buffer->len, DMA_TO_DEVICE);
-
 	priv->dmaops->tx_buffer(priv, buffer);
 
 	skb_tx_timestamp(skb);