net: gianfar: fix NVMEM mac address

If nvmem loads after the ethernet driver, mac address assignments will
not take effect. of_get_ethdev_address returns EPROBE_DEFER in such a
case so we need to handle that to avoid eth_hw_addr_random.

Signed-off-by: Rosen Penev <rosenp@gmail.com>
Reviewed-by: Simon Horman <horms@kernel.org>
Link: https://patch.msgid.link/20240910220913.14101-1-rosenp@gmail.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

Author: neheb

drivers/net/ethernet/freescale/gianfar.c

@@ -754,6 +754,8 @@ static int gfar_of_init(struct platform_device *ofdev, struct net_device **pdev)
 		priv->device_flags |= FSL_GIANFAR_DEV_HAS_BUF_STASHING;
 
 	err = of_get_ethdev_address(np, dev);
+	if (err == -EPROBE_DEFER)
+		goto err_grp_init;
 	if (err) {
 		eth_hw_addr_random(dev);
 		dev_info(&ofdev->dev, "Using random MAC address: %pM\n", dev->dev_addr);