serial: 8250_pci: Fill in rs485_supported for pci_fintek

Add information on supported serial_rs485 features.
Signed-off-by: Ilpo Järvinen <ilpo.jarvinen@linux.intel.com>
Link: https://lore.kernel.org/r/20220606100433.13793-12-ilpo.jarvinen@linux.intel.comSigned-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/tty/serial/8250/8250_pci.c

@@ -1597,6 +1597,11 @@ static int pci_fintek_rs485_config(struct uart_port *port,
 	return 0;
 }
 
+static const struct serial_rs485 pci_fintek_rs485_supported = {
+	.flags = SER_RS485_ENABLED | SER_RS485_RTS_ON_SEND,
+	/* F81504/508/512 does not support RTS delay before or after send */
+};
+
 static int pci_fintek_setup(struct serial_private *priv,
 			    const struct pciserial_board *board,
 			    struct uart_8250_port *port, int idx)
@@ -1616,6 +1621,7 @@ static int pci_fintek_setup(struct serial_private *priv,
 	port->port.iotype = UPIO_PORT;
 	port->port.iobase = iobase;
 	port->port.rs485_config = pci_fintek_rs485_config;
+	port->port.rs485_supported = &pci_fintek_rs485_supported;
 
 	data = devm_kzalloc(&pdev->dev, sizeof(u8), GFP_KERNEL);
 	if (!data)