net: mdio: Fix not calling dev_dbg with a device

The name of the device we are working on is `ethdev` and not just `dev`.

Signed-off-by: Sean Anderson <seanga2@gmail.com>
Tested-by: Patrick Delaunay <patrick.delaunay@st.com>
diff --git a/net/mdio-uclass.c b/net/mdio-uclass.c
index 66ee2e1..b5e8e46 100644
--- a/net/mdio-uclass.c
+++ b/net/mdio-uclass.c
@@ -145,7 +145,7 @@
 			break;
 
 	if (!ofnode_valid(phandle.node)) {
-		dev_dbg(dev, "can't find PHY node\n");
+		dev_dbg(ethdev, "can't find PHY node\n");
 		return NULL;
 	}
 
@@ -161,7 +161,7 @@
 	if (uclass_get_device_by_ofnode(UCLASS_MDIO,
 					ofnode_get_parent(phandle.node),
 					&mdiodev)) {
-		dev_dbg(dev, "can't find MDIO bus for node %s\n",
+		dev_dbg(ethdev, "can't find MDIO bus for node %s\n",
 			ofnode_get_name(ofnode_get_parent(phandle.node)));
 		return NULL;
 	}