watchdog: starfive: Fix resource leak in probe error path

If pm_runtime_put_sync() fails after watchdog_register_device()
succeeds, the probe function jumps to err_exit without
unregistering the watchdog device. This leaves the watchdog
registered in the subsystem while the driver fails to load,
resulting in a resource leak.

Add a new error label err_unregister_wdt to properly unregister
the watchdog device.

Fixes: 8bc22a2 ("watchdog: starfive: Check pm_runtime_enabled() before decrementing usage counter")
Signed-off-by: Haotian Zhang <vulab@iscas.ac.cn>
Reviewed-by: Wim Van Sebroeck <wim@linux-watchdog.org>
Signed-off-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Wim Van Sebroeck <wim@linux-watchdog.org>

Author: ISCAS-Vulab

drivers/watchdog/starfive-wdt.c

@@ -500,12 +500,14 @@ static int starfive_wdt_probe(struct platform_device *pdev)
 		if (pm_runtime_enabled(&pdev->dev)) {
 			ret = pm_runtime_put_sync(&pdev->dev);
 			if (ret)
-				goto err_exit;
+				goto err_unregister_wdt;
 		}
 	}
 
 	return 0;
 
+err_unregister_wdt:
+	watchdog_unregister_device(&wdt->wdd);
 err_exit:
 	starfive_wdt_disable_clock(wdt);
 	pm_runtime_disable(&pdev->dev);