tty/serial: atmel: reschedule TX after RX was started

BugLink: https://bugs.launchpad.net/bugs/1845405

commit d2ace81b upstream.

When half-duplex RS485 communication is used, after RX is started, TX
tasklet still needs to be  scheduled tasklet. This avoids console freezing
when more data is to be transmitted, if the serial communication is not
closed.

Fixes: 69646d7a ("tty/serial: atmel: RS485 HD w/DMA: enable RX after TX is stopped")
Signed-off-by: Razvan Stefanescu <razvan.stefanescu@microchip.com>
Cc: stable <stable@vger.kernel.org>
Link: https://lore.kernel.org/r/20190813074025.16218-1-razvan.stefanescu@microchip.comSigned-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Connor Kuehl <connor.kuehl@canonical.com>
Signed-off-by: Kleber Sacilotto de Souza <kleber.souza@canonical.com>

drivers/tty/serial/atmel_serial.c

@@ -1275,7 +1275,6 @@ atmel_handle_transmit(struct uart_port *port, unsigned int pending)
 
 			atmel_port->hd_start_rx = false;
 			atmel_start_rx(port);
-			return;
 		}
 
 		tasklet_schedule(&atmel_port->tasklet);