igb: Use dev_get_drvdata where possible

Instead of using to_pci_dev + pci_get_drvdata,
use dev_get_drvdata to make code simpler.
Signed-off-by: NChuhong Yuan <hslester96@gmail.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

drivers/net/ethernet/intel/igb/igb_main.c

@@ -8880,8 +8880,7 @@ static int __maybe_unused igb_resume(struct device *dev)
 
 static int __maybe_unused igb_runtime_idle(struct device *dev)
 {
-	struct pci_dev *pdev = to_pci_dev(dev);
-	struct net_device *netdev = pci_get_drvdata(pdev);
+	struct net_device *netdev = dev_get_drvdata(dev);
 	struct igb_adapter *adapter = netdev_priv(netdev);
 
 	if (!igb_has_link(adapter))