gpio: mxs: fix Wvoid-pointer-to-enum-cast warning

'devid' is an enum, thus cast of pointer on 64-bit compile test with W=1
causes:

  gpio-mxs.c:274:16: error: cast to smaller integer type 'enum mxs_gpio_id' from 'const void *' [-Werror,-Wvoid-pointer-to-enum-cast]
Signed-off-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>
Reviewed-by: Andy Shevchenko <andy.shevchenko@gmail.com>
Signed-off-by: Bartosz Golaszewski <bartosz.golaszewski@linaro.org>

drivers/gpio/gpio-mxs.c

@@ -271,7 +271,7 @@ static int mxs_gpio_probe(struct platform_device *pdev)
 	port->id = of_alias_get_id(np, "gpio");
 	if (port->id < 0)
 		return port->id;
-	port->devid = (enum mxs_gpio_id)of_device_get_match_data(&pdev->dev);
+	port->devid = (uintptr_t)of_device_get_match_data(&pdev->dev);
 	port->dev = &pdev->dev;
 	port->irq = platform_get_irq(pdev, 0);
 	if (port->irq < 0)