IXP4xx: Add PHYLIB MII ioctl to the Ethernet driver.

Signed-off-by: Krzysztof Hałasa <khc@pm.waw.pl>
diff --git a/drivers/net/arm/ixp4xx_eth.c b/drivers/net/arm/ixp4xx_eth.c
index db44ebbf..1bbb7b8 100644
--- a/drivers/net/arm/ixp4xx_eth.c
+++ b/drivers/net/arm/ixp4xx_eth.c
@@ -788,9 +788,11 @@
 
 static int eth_ioctl(struct net_device *dev, struct ifreq *req, int cmd)
 {
+	struct port *port = netdev_priv(dev);
+
 	if (!netif_running(dev))
 		return -EINVAL;
-	return -EINVAL;
+	return phy_mii_ioctl(port->phydev, if_mii(req), cmd);
 }