net: ethoc: don't advertise gigabit speed on attached PHY

OpenCores 10/100 Mbps MAC does not support speeds above 100 Mbps, but does
not disable advertisement when PHY supports them. This results in
non-functioning network when the MAC is connected to a gigabit PHY connected
to a gigabit switch.

The fix is to disable gigabit speed advertisement on attached PHY
unconditionally.
Signed-off-by: Max Filippov <jcmvbkbc@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

drivers/net/ethernet/ethoc.c

@@ -691,6 +691,11 @@ static int ethoc_mdio_probe(struct net_device *dev)
 	}
 
 	priv->phy = phy;
+	phy->advertising &= ~(ADVERTISED_1000baseT_Full |
+			      ADVERTISED_1000baseT_Half);
+	phy->supported &= ~(SUPPORTED_1000baseT_Full |
+			    SUPPORTED_1000baseT_Half);
+
 	return 0;
 }