serial: tegra: Remove redundant code and check in tegra_uart_stop_rx()

The serial-tegra driver always uses DMA and hence the driver always
allocates DMA channels. Therefore, the test to see if the RX DMA channel
is initialised in tegra_uart_stop_rx() is unnecessary and so remove
the test and the code that corresponds to the case where the RX DMA
channel is not initialised. Please note that the call to
tegra_uart_stop_rx() should always be before the call to
tegra_uart_shutdown() which will uninitialise the RX DMA channel.
Signed-off-by: Jon Hunter <jonathanh@nvidia.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/tty/serial/serial-tegra.c

@@ -777,16 +777,13 @@ static void tegra_uart_stop_rx(struct uart_port *u)
 	tup->ier_shadow = ier;
 	tegra_uart_write(tup, ier, UART_IER);
 	tup->rx_in_progress = 0;
-	if (tup->rx_dma_chan) {
 	dmaengine_terminate_all(tup->rx_dma_chan);
 	dmaengine_tx_status(tup->rx_dma_chan, tup->rx_cookie, &state);
 	async_tx_ack(tup->rx_dma_desc);
 	count = tup->rx_bytes_requested - state.residue;
 	tegra_uart_copy_rx_to_tty(tup, port, count);
 	tegra_uart_handle_rx_pio(tup, port);
-	} else {
-		tegra_uart_handle_rx_pio(tup, port);
-	}
+
 	if (tty) {
 		tty_flip_buffer_push(port);
 		tty_kref_put(tty);