net: ethernet: ti: am65-cpsw: fix error handling in am65_cpsw_nuss_probe()

The am65_cpsw_nuss_cleanup_ndev() function calls unregister_netdev()
even if register_netdev() fails, which triggers WARN_ON(1) in
unregister_netdevice_many(). To fix it, make sure that
unregister_netdev() is called only on registered netdev.

Compile tested only.

Fixes: 84b4aa49 ("net: ethernet: ti: am65-cpsw: add multi port support in mac-only mode")
Signed-off-by: Zhang Changzhong <zhangchangzhong@huawei.com>
Reviewed-by: Maciej Fijalkowski <maciej.fijalkowski@intel.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

drivers/net/ethernet/ti/am65-cpsw-nuss.c

@@ -2082,7 +2082,7 @@ static void am65_cpsw_nuss_cleanup_ndev(struct am65_cpsw_common *common)
 
 	for (i = 0; i < common->port_num; i++) {
 		port = &common->ports[i];
-		if (port->ndev)
+		if (port->ndev && port->ndev->reg_state == NETREG_REGISTERED)
 			unregister_netdev(port->ndev);
 	}
 }