watchdog: wm831x_wdt: Convert to use device managed functions

Use device managed functions to simplify error handling, reduce
source code size, improve readability, and reduce the likelyhood of bugs.

The conversion was done automatically with coccinelle using the
following semantic patches. The semantic patches and the scripts used
to generate this commit log are available at
https://github.com/groeck/coccinelle-patches

- Replace 'goto l; ... l: return e;' with 'return e;'
- Replace 'val = e; return val;' with 'return e;'
- Drop assignments to otherwise unused variables
- Replace 'if (e) { return expr; }' with 'if (e) return expr;'
- Drop remove function
- Drop platform_set_drvdata()
- Use devm_watchdog_register_driver() to register watchdog device

Acked-by: Charles Keepax <[e-mail]>
Signed-off-by: Guenter Roeck <[e-mail]>

drivers/watchdog/wm831x_wdt.c

···
 	if (ret < 0) {
 		dev_err(wm831x->dev, "Failed to read watchdog status: %d\n",
 			ret);
-		goto err;
+		return ret;
 	}
 	reg = ret;
 
···
 
 	driver_data = devm_kzalloc(&pdev->dev, sizeof(*driver_data),
 				   GFP_KERNEL);
-	if (!driver_data) {
-		ret = -ENOMEM;
-		goto err;
-	}
+	if (!driver_data)
+		return -ENOMEM;
 
 	mutex_init(&driver_data->lock);
 	driver_data->wm831x = wm831x;
···
 				dev_err(wm831x->dev,
 					"Failed to request update GPIO: %d\n",
 					ret);
-				goto err;
+				return ret;
 			}
 
 			driver_data->update_gpio = pdata->update_gpio;
···
 		} else {
 			dev_err(wm831x->dev,
 				"Failed to unlock security key: %d\n", ret);
-			goto err;
+			return ret;
 		}
 	}
 
-	ret = watchdog_register_device(&driver_data->wdt);
+	ret = devm_watchdog_register_device(&pdev->dev, &driver_data->wdt);
 	if (ret != 0) {
 		dev_err(wm831x->dev, "watchdog_register_device() failed: %d\n",
 			ret);
-		goto err;
+		return ret;
 	}
-
-	platform_set_drvdata(pdev, driver_data);
-
-	return 0;
-
-err:
-	return ret;
-}
-
-static int wm831x_wdt_remove(struct platform_device *pdev)
-{
-	struct wm831x_wdt_drvdata *driver_data = platform_get_drvdata(pdev);
-
-	watchdog_unregister_device(&driver_data->wdt);
 
 	return 0;
 }
 
 static struct platform_driver wm831x_wdt_driver = {
 	.probe = wm831x_wdt_probe,
-	.remove = wm831x_wdt_remove,
 	.driver = {
 		.name = "wm831x-watchdog",
 	},