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-arizona.c b/drivers/gpio/gpio-arizona.c
index 0ea853f..fa8b6a7 100644
--- a/drivers/gpio/gpio-arizona.c
+++ b/drivers/gpio/gpio-arizona.c
@@ -97,7 +97,7 @@
 static int arizona_gpio_probe(struct platform_device *pdev)
 {
 	struct arizona *arizona = dev_get_drvdata(pdev->dev.parent);
-	struct arizona_pdata *pdata = arizona->dev->platform_data;
+	struct arizona_pdata *pdata = dev_get_platdata(arizona->dev);
 	struct arizona_gpio *arizona_gpio;
 	int ret;