serial: fsl_lpuart: remove manual RTSCTS control from 8-bit LPUART

The LPUART doesn't have the ability to control the RTS or CTS line
manually. Instead it will set it automatically when data is send or
handle it when data is received. Thus drop the wrong code in set_mctrl.
For the 32 bit version this was already done in the commit 2b30efe2e8
("tty: serial: lpuart: Remove unnecessary code from set_mctrl"). Keep
the 8-bit version in sync and remove it there, too.

Signed-off-by: Michael Walle <michael@walle.cc>
Link: https://lore.kernel.org/r/20210512141255.18277-8-michael@walle.cc
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/tty/serial/fsl_lpuart.c

@@ -1403,17 +1403,7 @@ static int lpuart32_config_rs485(struct uart_port *port,
 
 static unsigned int lpuart_get_mctrl(struct uart_port *port)
 {
-	unsigned int temp = 0;
-	unsigned char reg;
-
-	reg = readb(port->membase + UARTMODEM);
-	if (reg & UARTMODEM_TXCTSE)
-		temp |= TIOCM_CTS;
-
-	if (reg & UARTMODEM_RXRTSE)
-		temp |= TIOCM_RTS;
-
-	return temp;
+	return 0;
 }
 
 static unsigned int lpuart32_get_mctrl(struct uart_port *port)
@@ -1423,23 +1413,7 @@ static unsigned int lpuart32_get_mctrl(struct uart_port *port)
 
 static void lpuart_set_mctrl(struct uart_port *port, unsigned int mctrl)
 {
-	unsigned char temp;
-	struct lpuart_port *sport = container_of(port,
-				struct lpuart_port, port);
 
-	/* Make sure RXRTSE bit is not set when RS485 is enabled */
-	if (!(sport->port.rs485.flags & SER_RS485_ENABLED)) {
-		temp = readb(sport->port.membase + UARTMODEM) &
-			~(UARTMODEM_RXRTSE | UARTMODEM_TXCTSE);
-
-		if (mctrl & TIOCM_RTS)
-			temp |= UARTMODEM_RXRTSE;
-
-		if (mctrl & TIOCM_CTS)
-			temp |= UARTMODEM_TXCTSE;
-
-		writeb(temp, port->membase + UARTMODEM);
-	}
 }
 
 static void lpuart32_set_mctrl(struct uart_port *port, unsigned int mctrl)