serial: imx: remove redundant assignment in rs485_config

serial: imx: remove redundant assignment in rs485_config

In uart_set_rs485_config() the serial core already assigns the passed
serial_rs485 struct to the uart port.

So remove the assignment in the drivers rs485_config() function to avoid
reduncancy.

Acked-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Signed-off-by: Lino Sanfilippo <LinoSanfilippo@gmx.de>
Link: https://lore.kernel.org/r/20220410104642.32195-8-LinoSanfilippo@gmx.de
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>