phy: micrel: Fix finding PHY properties in MAC node for KSZ9031.

Commit 651df218 ("phy: micrel: Fix finding PHY properties in MAC
 node.") only fixes finding PHY properties in MAC node for KSZ9021. This
commit applies the same fix for KSZ9031.

Fixes: 8b63ec18 ("phylib: Make PHYs children of their MDIO bus, not the bus' parent.")
Acked-by: Andrew Lunn <andrew@lunn.ch>
Signed-off-by: Henri Roosen <henri.roosen@ginzinger.com>
Signed-off-by: David S. Miller <davem@davemloft.net>