serial: tegra: Fix cookie used by TX channel

The DMA cookie for the RX channel is being used by the TX channel.
Therefore, fix driver to use the correct DMA cookie for the TX channel.
Signed-off-by: Jon Hunter <jonathanh@nvidia.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/tty/serial/serial-tegra.c

@@ -410,7 +410,7 @@ static void tegra_uart_tx_dma_complete(void *args)
 	unsigned long flags;
 	unsigned int count;
 
-	dmaengine_tx_status(tup->tx_dma_chan, tup->rx_cookie, &state);
+	dmaengine_tx_status(tup->tx_dma_chan, tup->tx_cookie, &state);
 	count = tup->tx_bytes_requested - state.residue;
 	async_tx_ack(tup->tx_dma_desc);
 	spin_lock_irqsave(&tup->uport.lock, flags);