watchdog: ath79_wdt: Use the devm_clk_get_enabled() helper function

The devm_clk_get_enabled() helper:
    - calls devm_clk_get()
    - calls clk_prepare_enable() and registers what is needed in order to
      call clk_disable_unprepare() when needed, as a managed resource.

This simplifies the code.
Signed-off-by: Jinjie Ruan <ruanjinjie@huawei.com>
Reviewed-by: Guenter Roeck <linux@roeck-us.net>
Link: https://lore.kernel.org/r/20230824135514.2661364-3-ruanjinjie@huawei.comSigned-off-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Wim Van Sebroeck <wim@linux-watchdog.org>

drivers/watchdog/ath79_wdt.c

@@ -257,19 +257,13 @@ static int ath79_wdt_probe(struct platform_device *pdev)
 	if (IS_ERR(wdt_base))
 		return PTR_ERR(wdt_base);
 
-	wdt_clk = devm_clk_get(&pdev->dev, "wdt");
+	wdt_clk = devm_clk_get_enabled(&pdev->dev, "wdt");
 	if (IS_ERR(wdt_clk))
 		return PTR_ERR(wdt_clk);
 
-	err = clk_prepare_enable(wdt_clk);
-	if (err)
-		return err;
-
 	wdt_freq = clk_get_rate(wdt_clk);
-	if (!wdt_freq) {
-		err = -EINVAL;
-		goto err_clk_disable;
-	}
+	if (!wdt_freq)
+		return -EINVAL;
 
 	max_timeout = (0xfffffffful / wdt_freq);
 	if (timeout < 1 || timeout > max_timeout) {
@@ -286,20 +280,15 @@ static int ath79_wdt_probe(struct platform_device *pdev)
 	if (err) {
 		dev_err(&pdev->dev,
 			"unable to register misc device, err=%d\n", err);
-		goto err_clk_disable;
+		return err;
 	}
 
 	return 0;
-
-err_clk_disable:
-	clk_disable_unprepare(wdt_clk);
-	return err;
 }
 
 static void ath79_wdt_remove(struct platform_device *pdev)
 {
 	misc_deregister(&ath79_wdt_miscdev);
-	clk_disable_unprepare(wdt_clk);
 }
 
 static void ath79_wdt_shutdown(struct platform_device *pdev)