net: mv643xx_eth: use phy_disconnect instead of phy_detach

Using a separated mdio bus driver with mvmdio, phy_detach on network device
removal will not stop the phy and finally lead to NULL pointer dereference
in mvmdio due to non-existent network device. Use phy_disconnect instead
to properly stop phy device from accessing network device prior removal of
the network device.
Signed-off-by: NSebastian Hesselbarth <sebastian.hesselbarth@gmail.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

drivers/net/ethernet/marvell/mv643xx_eth.c

@@ -2805,7 +2805,7 @@ static int mv643xx_eth_remove(struct platform_device *pdev)
 
 	unregister_netdev(mp->dev);
 	if (mp->phy != NULL)
-		phy_detach(mp->phy);
+		phy_disconnect(mp->phy);
 	cancel_work_sync(&mp->tx_timeout_task);
 
 	if (!IS_ERR(mp->clk))