net: 8139too: remove unnecessary pci_set_drvdata()

The driver core clears the driver data to NULL after device_release
or on probe failure. Thus, it is not needed to manually clear the
device driver data to NULL.
Signed-off-by: NJingoo Han <jg1.han@samsung.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

drivers/net/ethernet/realtek/8139too.c

@@ -727,7 +727,6 @@ static void __rtl8139_cleanup_dev (struct net_device *dev)
 	pci_release_regions (pdev);
 
 	free_netdev(dev);
-	pci_set_drvdata (pdev, NULL);
 }