net: macb: Fix handling of fixed-link node

net: macb: Fix handling of fixed-link node

[ Upstream commit 79540d133ed6f65a37dacb54b7a704cc8a24c52d ]

fixed-link nodes are treated as PHY nodes by of_mdiobus_child_is_phy().
We must check if the interface is a fixed-link before looking up for PHY
nodes.

Fixes: 7897b071ac3b ("net: macb: convert to phylink")
Tested-by: Cristian Birsan <cristian.birsan@microchip.com>
Signed-off-by: Codrin Ciubotariu <codrin.ciubotariu@microchip.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>