gpio: use dev_get_platdata()

Use the wrapper function for retrieving the platform data instead of
accessing dev->platform_data directly.

Signed-off-by: Jingoo Han <jg1.han@samsung.com>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
diff --git a/drivers/gpio/gpio-wm831x.c b/drivers/gpio/gpio-wm831x.c
index 2a743e1..456000c 100644
--- a/drivers/gpio/gpio-wm831x.c
+++ b/drivers/gpio/gpio-wm831x.c
@@ -246,7 +246,7 @@
 static int wm831x_gpio_probe(struct platform_device *pdev)
 {
 	struct wm831x *wm831x = dev_get_drvdata(pdev->dev.parent);
-	struct wm831x_pdata *pdata = wm831x->dev->platform_data;
+	struct wm831x_pdata *pdata = dev_get_platdata(wm831x->dev);
 	struct wm831x_gpio *wm831x_gpio;
 	int ret;