serial: max310x: Use uart_xmit_advance()

Take advantage of the new uart_xmit_advance() helper.
Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Signed-off-by: Ilpo Järvinen <ilpo.jarvinen@linux.intel.com>
Link: https://lore.kernel.org/r/20221019091151.6692-22-ilpo.jarvinen@linux.intel.comSigned-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/tty/serial/max310x.c

@@ -787,10 +787,7 @@ static void max310x_handle_tx(struct uart_port *port)
 		} else {
 			max310x_batch_write(port, xmit->buf + xmit->tail, to_send);
 		}
-
-		/* Add data to send */
-		port->icount.tx += to_send;
-		xmit->tail = (xmit->tail + to_send) & (UART_XMIT_SIZE - 1);
+		uart_xmit_advance(port, to_send);
 	}
 
 	if (uart_circ_chars_pending(xmit) < WAKEUP_CHARS)