usb: cdns3: Fix runtime PM imbalance on error

When cdns3_gadget_start() fails, a pairing PM usage counter
decrement is needed to keep the counter balanced.
Signed-off-by: Dinghao Liu <dinghao.liu@zju.edu.cn>
Link: https://lore.kernel.org/r/20210412054908.7975-1-dinghao.liu@zju.edu.cnSigned-off-by: Peter Chen <peter.chen@kernel.org>

drivers/usb/cdns3/cdns3-gadget.c

@@ -3268,8 +3268,10 @@ static int __cdns3_gadget_init(struct cdns *cdns)
 	pm_runtime_get_sync(cdns->dev);
 
 	ret = cdns3_gadget_start(cdns);
-	if (ret)
+	if (ret) {
+		pm_runtime_put_sync(cdns->dev);
 		return ret;
+	}
 
 	/*
 	 * Because interrupt line can be shared with other components in