This prepares *of_device_id.data becoming const. Without this change the
following warning would occur:
	drivers/tty/serial/imx.c: In function 'serial_imx_probe_dt':
	drivers/tty/serial/imx.c:1430:17: warning: assignment discards 'const' qualifier from pointer target type [enabled by default]
Acked-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
        unsigned short          trcv_delay; /* transceiver delay */
        struct clk              *clk_ipg;
        struct clk              *clk_per;
-       struct imx_uart_data    *devdata;
+       const struct imx_uart_data *devdata;
 };
 
 struct imx_port_ucrs {