ti_cpsw: Check for disabled child nodes

Dual MAC devices don't necessarily have both MACs wired up, so ignore
those that are disabled.
Signed-off-by: NBen Hutchings <ben.hutchings@codethink.co.uk>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

drivers/net/ethernet/ti/cpsw.c

@@ -2014,7 +2014,7 @@ static int cpsw_probe_dt(struct cpsw_platform_data *data,
 	if (ret)
 		dev_warn(&pdev->dev, "Doesn't have any child node\n");
 
-	for_each_child_of_node(node, slave_node) {
+	for_each_available_child_of_node(node, slave_node) {
 		struct cpsw_slave_data *slave_data = data->slave_data + i;
 		const void *mac_addr = NULL;
 		int lenp;