gpio: wm8994: remove platform_set_drvdata() + cleanup probe

The platform_set_drvdata() call is only useful if we need to retrieve back
the private information.
Since the driver doesn't do that, it's not useful to have it.

If this is removed, we can also just do a direct return on
devm_gpiochip_add_data(). We don't need to print that this call failed as
there are other ways to log/see this during probe.

Signed-off-by: Alexandru Ardelean <[e-mail]>
Signed-off-by: Bartosz Golaszewski <[e-mail]>

drivers/gpio/gpio-wm8994.c

···
 	struct wm8994 *wm8994 = dev_get_drvdata(pdev->dev.parent);
 	struct wm8994_pdata *pdata = dev_get_platdata(wm8994->dev);
 	struct wm8994_gpio *wm8994_gpio;
-	int ret;
 
 	wm8994_gpio = devm_kzalloc(&pdev->dev, sizeof(*wm8994_gpio),
 				   GFP_KERNEL);
···
 	else
 		wm8994_gpio->gpio_chip.base = -1;
 
-	ret = devm_gpiochip_add_data(&pdev->dev, &wm8994_gpio->gpio_chip,
-				     wm8994_gpio);
-	if (ret < 0) {
-		dev_err(&pdev->dev, "Could not register gpiochip, %d\n",
-			ret);
-		return ret;
-	}
-
-	platform_set_drvdata(pdev, wm8994_gpio);
-
-	return ret;
+	return devm_gpiochip_add_data(&pdev->dev, &wm8994_gpio->gpio_chip, wm8994_gpio);
 }
 
 static struct platform_driver wm8994_gpio_driver = {