serial: omap8250: Drop rx buffer sync

commit 27c310c5c312 ("serial: 8250_dma: no need to sync RX buffer")
notes the RX DMA buffer is allocated from DMA coherent memory, and
thus does not need sync'd for each transaction. The same is true
for OMAP RX DMA.

Signed-off-by: Peter Hurley <peter@hurleysoftware.com>
Reviewed-by: Heikki Krogerus <heikki.krogerus@linux.intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/tty/serial/8250/8250_omap.c

@@ -754,9 +754,6 @@ static void __dma_rx_do_complete(struct uart_8250_port *p, bool error)
 	unsigned long		flags;
 	int			ret;
 
-	dma_sync_single_for_cpu(dma->rxchan->device->dev, dma->rx_addr,
-				dma->rx_size, DMA_FROM_DEVICE);
-
 	spin_lock_irqsave(&priv->rx_dma_lock, flags);
 
 	if (!dma->rx_running)
@@ -868,9 +865,6 @@ static int omap_8250_rx_dma(struct uart_8250_port *p, unsigned int iir)
 
 	dma->rx_cookie = dmaengine_submit(desc);
 
-	dma_sync_single_for_device(dma->rxchan->device->dev, dma->rx_addr,
-				   dma->rx_size, DMA_FROM_DEVICE);
-
 	dma_async_issue_pending(dma->rxchan);
 out:
 	spin_unlock_irqrestore(&priv->rx_dma_lock, flags);