serial: 8250_of: Use serial8250_em485_supported

8250_of uses em485, fill in rs485_supported accordingly.
Signed-off-by: Ilpo Järvinen <ilpo.jarvinen@linux.intel.com>
Link: https://lore.kernel.org/r/20220606100433.13793-11-ilpo.jarvinen@linux.intel.comSigned-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/tty/serial/8250/8250_of.c

@@ -165,6 +165,7 @@ static int of_platform_serial_setup(struct platform_device *ofdev,
 
 	port->dev = &ofdev->dev;
 	port->rs485_config = serial8250_em485_config;
+	port->rs485_supported = &serial8250_em485_supported;
 	up->rs485_start_tx = serial8250_em485_start_tx;
 	up->rs485_stop_tx = serial8250_em485_stop_tx;