watchdog: at91sam9_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: Claudiu Beznea <claudiu.beznea@tuxon.dev>
Reviewed-by: Guenter Roeck <linux@roeck-us.net>
Link: https://lore.kernel.org/r/20230824135514.2661364-2-ruanjinjie@huawei.com
Signed-off-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Wim Van Sebroeck <wim@linux-watchdog.org>

Author: ruanjinjie-eng

drivers/watchdog/at91sam9_wdt.c

@@ -348,37 +348,28 @@ static int __init at91wdt_probe(struct platform_device *pdev)
 	if (IS_ERR(wdt->base))
 		return PTR_ERR(wdt->base);
 
-	wdt->sclk = devm_clk_get(&pdev->dev, NULL);
-	if (IS_ERR(wdt->sclk))
-		return PTR_ERR(wdt->sclk);
-
-	err = clk_prepare_enable(wdt->sclk);
-	if (err) {
+	wdt->sclk = devm_clk_get_enabled(&pdev->dev, NULL);
+	if (IS_ERR(wdt->sclk)) {
 		dev_err(&pdev->dev, "Could not enable slow clock\n");
-		return err;
+		return PTR_ERR(wdt->sclk);
 	}
 
 	if (pdev->dev.of_node) {
 		err = of_at91wdt_init(pdev->dev.of_node, wdt);
 		if (err)
-			goto err_clk;
+			return err;
 	}
 
 	err = at91_wdt_init(pdev, wdt);
 	if (err)
-		goto err_clk;
+		return err;
 
 	platform_set_drvdata(pdev, wdt);
 
 	pr_info("enabled (heartbeat=%d sec, nowayout=%d)\n",
 		wdt->wdd.timeout, wdt->nowayout);
 
 	return 0;
-
-err_clk:
-	clk_disable_unprepare(wdt->sclk);
-
-	return err;
 }
 
 static int __exit at91wdt_remove(struct platform_device *pdev)
@@ -388,7 +379,6 @@ static int __exit at91wdt_remove(struct platform_device *pdev)
 
 	pr_warn("I quit now, hardware will probably reboot!\n");
 	del_timer(&wdt->timer);
-	clk_disable_unprepare(wdt->sclk);
 
 	return 0;
 }