serial: stm32: fix initialization of RS485 mode

Configure RS485 mode during port initialization.

Fixes: 1bcda09d2910 ("serial: stm32: add support for RS485 hardware control mode")
Signed-off-by: Bich Hemon <bich.hemon@st.com>
Acked-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/tty/serial/stm32-usart.c

@@ -809,6 +809,10 @@ static int stm32_init_port(struct stm32_port *stm32port,
 	port->ops	= &stm32_uart_ops;
 	port->dev	= &pdev->dev;
 	port->irq	= platform_get_irq(pdev, 0);
+	port->rs485_config = stm32_config_rs485;
+
+	stm32_init_rs485(port, pdev);
+
 	stm32port->wakeirq = platform_get_irq(pdev, 1);
 	stm32port->fifoen = stm32port->info->cfg.has_fifo;