serial: 8250: omap: Use serial8250_em485_supported

8250_omap uses em485, fill in rs485_supported accordingly. This makes
RS485 work with 8250_omap again, which was broken with the introduction
of the RS485 config sanitization.

Fixes: be2e2cb ("serial: Sanitize rs485_struct")
Reviewed-by: Ilpo Järvinen <ilpo.jarvinen@linux.intel.com>
Signed-off-by: Matthias Schiffer <matthias.schiffer@ew.tq-group.com>
Link: https://lore.kernel.org/r/20220916110955.161099-1-matthias.schiffer@ew.tq-group.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

Author: tq-schiffern

drivers/tty/serial/8250/8250_omap.c

@@ -1334,6 +1334,7 @@ static int omap8250_probe(struct platform_device *pdev)
 	up.port.throttle = omap_8250_throttle;
 	up.port.unthrottle = omap_8250_unthrottle;
 	up.port.rs485_config = serial8250_em485_config;
+	up.port.rs485_supported = serial8250_em485_supported;
 	up.rs485_start_tx = serial8250_em485_start_tx;
 	up.rs485_stop_tx = serial8250_em485_stop_tx;
 	up.port.has_sysrq = IS_ENABLED(CONFIG_SERIAL_8250_CONSOLE);