skge: crash on shutdown/suspend

If device is not fails during module startup (like unsupported chip
version) then driver would crash dereferencing a null pointer, on shutdown
or suspend/resume.
Signed-off-by: Stephen Hemminger <shemminger@linux-foundation.org>
Signed-off-by: Jeff Garzik <jeff@garzik.org>

drivers/net/skge.c

@@ -3802,6 +3802,9 @@ static int skge_suspend(struct pci_dev *pdev, pm_message_t state)
 	struct skge_hw *hw  = pci_get_drvdata(pdev);
 	int i, err, wol = 0;
 
+	if (!hw)
+		return 0;
+
 	err = pci_save_state(pdev);
 	if (err)
 		return err;
@@ -3830,6 +3833,9 @@ static int skge_resume(struct pci_dev *pdev)
 	struct skge_hw *hw  = pci_get_drvdata(pdev);
 	int i, err;
 
+	if (!hw)
+		return 0;
+
 	err = pci_set_power_state(pdev, PCI_D0);
 	if (err)
 		goto out;
@@ -3868,6 +3874,9 @@ static void skge_shutdown(struct pci_dev *pdev)
 	struct skge_hw *hw  = pci_get_drvdata(pdev);
 	int i, wol = 0;
 
+	if (!hw)
+		return;
+
 	for (i = 0; i < hw->ports; i++) {
 		struct net_device *dev = hw->dev[i];
 		struct skge_port *skge = netdev_priv(dev);