FogBugz #189738: Correct code to obtain mdio child node from devicetree

The code to obtain the mdio child node accidentally worked for the
devicetree used for testing, and was incorrect for arbitrary devicetrees.
This patch corrects that problem found during community review.

Signed-off-by: Vince Bridgers <[email protected]>

Author: Vince Bridgers

drivers/net/ethernet/altera/altera_tse_main.c

@@ -129,11 +129,16 @@ static int altera_tse_mdio_create(struct net_device *dev, unsigned int id)
 	struct altera_tse_private *priv = netdev_priv(dev);
 	int ret;
 	int i;
-	struct device_node *mdio_node;
-	struct mii_bus *mdio;
+	struct device_node *mdio_node = NULL;
+	struct mii_bus *mdio = NULL;
+	struct device_node *child_node = NULL;
 
-	mdio_node = of_find_compatible_node(priv->device->of_node, NULL,
-		"altr,tse-mdio");
+	for_each_child_of_node(priv->device->of_node, child_node) {
+		if (of_device_is_compatible(child_node, "altr,tse-mdio")) {
+			mdio_node = child_node;
+			break;
+		}
+	}
 
 	if (mdio_node) {
 		dev_dbg(priv->device, "FOUND MDIO subnode\n");