watchdog: moxart_wdt: Convert to use device managed functions and other improvements

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

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

- Drop assignments to otherwise unused variables
- Drop empty remove function
- Replace 'of_clk_get(np, 0)' with 'devm_clk_get(dev, NULL)'
- Use local variable 'struct device *dev' consistently
- Replace stop on remove with call to watchdog_stop_on_unregister()
- Use devm_watchdog_register_driver() to register watchdog device

Signed-off-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Wim Van Sebroeck <wim@linux-watchdog.org>

drivers/watchdog/moxart_wdt.c

@@ -91,7 +91,6 @@ static int moxart_wdt_probe(struct platform_device *pdev)
 {
 	struct moxart_wdt_dev *moxart_wdt;
 	struct device *dev = &pdev->dev;
-	struct device_node *node = dev->of_node;
 	struct clk *clk;
 	int err;
 	unsigned int max_timeout;
@@ -107,7 +106,7 @@ static int moxart_wdt_probe(struct platform_device *pdev)
 	if (IS_ERR(moxart_wdt->base))
 		return PTR_ERR(moxart_wdt->base);
 
-	clk = of_clk_get(node, 0);
+	clk = devm_clk_get(dev, NULL);
 	if (IS_ERR(clk)) {
 		pr_err("%s: of_clk_get failed\n", __func__);
 		return PTR_ERR(clk);
@@ -134,7 +133,8 @@ static int moxart_wdt_probe(struct platform_device *pdev)
 
 	watchdog_set_drvdata(&moxart_wdt->dev, moxart_wdt);
 
-	err = watchdog_register_device(&moxart_wdt->dev);
+	watchdog_stop_on_unregister(&moxart_wdt->dev);
+	err = devm_watchdog_register_device(dev, &moxart_wdt->dev);
 	if (err)
 		return err;
 
@@ -144,15 +144,6 @@ static int moxart_wdt_probe(struct platform_device *pdev)
 	return 0;
 }
 
-static int moxart_wdt_remove(struct platform_device *pdev)
-{
-	struct moxart_wdt_dev *moxart_wdt = platform_get_drvdata(pdev);
-
-	moxart_wdt_stop(&moxart_wdt->dev);
-
-	return 0;
-}
-
 static const struct of_device_id moxart_watchdog_match[] = {
 	{ .compatible = "moxa,moxart-watchdog" },
 	{ },
@@ -161,7 +152,6 @@ MODULE_DEVICE_TABLE(of, moxart_watchdog_match);
 
 static struct platform_driver moxart_wdt_driver = {
 	.probe      = moxart_wdt_probe,
-	.remove     = moxart_wdt_remove,
 	.driver     = {
 		.name		= "moxart-watchdog",
 		.of_match_table	= moxart_watchdog_match,