sh_eth: fix unused variable warning

Commit d5e07e69218fd9aa21d6c8c5ccc629d92bdb9b0f (sh_eth: use managed device API)
has caused this warning (due to my overlook):

drivers/net/ethernet/renesas/sh_eth.c: In function `sh_eth_drv_remove':
drivers/net/ethernet/renesas/sh_eth.c:2482:25: warning: unused variable `mdp'
[-Wunused-variable]

Kill the darn variable now...

Signed-off-by: Sergei Shtylyov <sergei.shtylyov@cogentembedded.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

drivers/net/ethernet/renesas/sh_eth.c

@@ -2479,7 +2479,6 @@ out:
 static int sh_eth_drv_remove(struct platform_device *pdev)
 {
 	struct net_device *ndev = platform_get_drvdata(pdev);
-	struct sh_eth_private *mdp = netdev_priv(ndev);
 
 	sh_mdio_release(ndev);
 	unregister_netdev(ndev);