r8169: fix setting driver_data after register_netdev

pci_set_drvdata() is called only after registering the net_device,
therefore we could run into a NPE if one of the functions using
driver_data is called before it's set.

Fix this by calling pci_set_drvdata() before registering the
net_device.

This fix is a candidate for stable. As far as I can see the
bug has been there in kernel version 3.2 already, therefore
I can't provide a reference which commit is fixed by it.

The fix may need small adjustments per kernel version because
due to other changes the label which is jumped to if
register_netdev() fails has changed over time.
Reported-by: David Miller <davem@davemloft.net>
Signed-off-by: Heiner Kallweit <hkallweit1@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

drivers/net/ethernet/realtek/r8169.c

@@ -8660,12 +8660,12 @@ static int rtl_init_one(struct pci_dev *pdev, const struct pci_device_id *ent)
 	if (!tp->counters)
 		return -ENOMEM;
 
+	pci_set_drvdata(pdev, dev);
+
 	rc = register_netdev(dev);
 	if (rc < 0)
 		return rc;
 
-	pci_set_drvdata(pdev, dev);
-
 	netif_info(tp, probe, dev, "%s at 0x%p, %pM, XID %08x IRQ %d\n",
 		   rtl_chip_infos[chipset].name, ioaddr, dev->dev_addr,
 		   (u32)(RTL_R32(TxConfig) & 0x9cf0f8ff), pdev->irq);