watchdog: cadence_wdt: use to_platform_device()

Use to_platform_device() instead of open-coding it.
Signed-off-by: Geliang Tang <geliangtang@163.com>
Signed-off-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Wim Van Sebroeck <wim@iguana.be>

drivers/watchdog/cadence_wdt.c

@@ -421,8 +421,7 @@ static void cdns_wdt_shutdown(struct platform_device *pdev)
  */
 static int __maybe_unused cdns_wdt_suspend(struct device *dev)
 {
-	struct platform_device *pdev = container_of(dev,
-			struct platform_device, dev);
+	struct platform_device *pdev = to_platform_device(dev);
 	struct cdns_wdt *wdt = platform_get_drvdata(pdev);
 
 	cdns_wdt_stop(&wdt->cdns_wdt_device);
@@ -440,8 +439,7 @@ static int __maybe_unused cdns_wdt_suspend(struct device *dev)
 static int __maybe_unused cdns_wdt_resume(struct device *dev)
 {
 	int ret;
-	struct platform_device *pdev = container_of(dev,
-			struct platform_device, dev);
+	struct platform_device *pdev = to_platform_device(dev);
 	struct cdns_wdt *wdt = platform_get_drvdata(pdev);
 
 	ret = clk_prepare_enable(wdt->clk);