serial: sc16is7xx: remove redundant check in rs485_config

In uart_set_rs485_config() the serial core already ensures that only one of
both options RTS on send or RTS after send is set.

So remove this check from the drivers rs485_config() function to avoid
redundancy.
Signed-off-by: Lino Sanfilippo <LinoSanfilippo@gmx.de>
Link: https://lore.kernel.org/r/20220410104642.32195-5-LinoSanfilippo@gmx.deSigned-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/tty/serial/sc16is7xx.c

@@ -1134,16 +1134,6 @@ static int sc16is7xx_config_rs485(struct uart_port *port,
 	struct sc16is7xx_one *one = to_sc16is7xx_one(port, port);
 
 	if (rs485->flags & SER_RS485_ENABLED) {
-		bool rts_during_rx, rts_during_tx;
-
-		rts_during_rx = rs485->flags & SER_RS485_RTS_AFTER_SEND;
-		rts_during_tx = rs485->flags & SER_RS485_RTS_ON_SEND;
-
-		if (rts_during_rx == rts_during_tx)
-			dev_err(port->dev,
-				"unsupported RTS signalling on_send:%d after_send:%d - exactly one of RS485 RTS flags should be set\n",
-				rts_during_tx, rts_during_rx);
-
 		/*
 		 * RTS signal is handled by HW, it's timing can't be influenced.
 		 * However, it's sometimes useful to delay TX even without RTS