net: ftgmac100: add missing error return code in ftgmac100_probe()

The variables will be free on path err_phy_connect, it should
return error code, or it will cause double free when calling
ftgmac100_remove().

Fixes: bd466c3f ("net/faraday: Support NCSI mode")
Fixes: 39bfab88 ("net: ftgmac100: Add support for DT phy-handle property")
Reported-by: NHulk Robot <hulkci@huawei.com>
Signed-off-by: NYang Yingliang <yangyingliang@huawei.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

drivers/net/ethernet/faraday/ftgmac100.c

@@ -1830,14 +1830,17 @@ static int ftgmac100_probe(struct platform_device *pdev)
 	if (np && of_get_property(np, "use-ncsi", NULL)) {
 		if (!IS_ENABLED(CONFIG_NET_NCSI)) {
 			dev_err(&pdev->dev, "NCSI stack not enabled\n");
+			err = -EINVAL;
 			goto err_phy_connect;
 		}
 
 		dev_info(&pdev->dev, "Using NCSI interface\n");
 		priv->use_ncsi = true;
 		priv->ndev = ncsi_register_dev(netdev, ftgmac100_ncsi_handler);
-		if (!priv->ndev)
+		if (!priv->ndev) {
+			err = -EINVAL;
 			goto err_phy_connect;
+		}
 	} else if (np && of_get_property(np, "phy-handle", NULL)) {
 		struct phy_device *phy;
 
@@ -1856,6 +1859,7 @@ static int ftgmac100_probe(struct platform_device *pdev)
 					     &ftgmac100_adjust_link);
 		if (!phy) {
 			dev_err(&pdev->dev, "Failed to connect to phy\n");
+			err = -EINVAL;
 			goto err_phy_connect;
 		}