serial: uartlite: Use uart_xmit_advance()

Take advantage of the new uart_xmit_advance() helper.
Signed-off-by: Ilpo Järvinen <ilpo.jarvinen@linux.intel.com>
Link: https://lore.kernel.org/r/20221019091151.6692-42-ilpo.jarvinen@linux.intel.comSigned-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/tty/serial/uartlite.c

@@ -203,8 +203,7 @@ static int ulite_transmit(struct uart_port *port, int stat)
 		return 0;
 
 	uart_out32(xmit->buf[xmit->tail], ULITE_TX, port);
-	xmit->tail = (xmit->tail + 1) & (UART_XMIT_SIZE-1);
-	port->icount.tx++;
+	uart_xmit_advance(port, 1);
 
 	/* wake up */
 	if (uart_circ_chars_pending(xmit) < WAKEUP_CHARS)