ixgb: return PCI_ERS_RESULT_DISCONNECT on permanent failure

PCI drivers that implement the struct pci_error_handlers' error_detected
callback should return PCI_ERS_RESULT_DISCONNECT if the state passed in is
pci_channel_io_perm_failure. This patch fixes the issue for ixgb.

Signed-off-by: Dean Nelson <dnelson@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/drivers/net/ixgb/ixgb_main.c b/drivers/net/ixgb/ixgb_main.c
index eb917f1..fad08ce 100644
--- a/drivers/net/ixgb/ixgb_main.c
+++ b/drivers/net/ixgb/ixgb_main.c
@@ -2227,6 +2227,11 @@
 	struct net_device *netdev = pci_get_drvdata(pdev);
 	struct ixgb_adapter *adapter = netdev_priv(netdev);
 
+	netif_device_detach(netdev);
+
+	if (state == pci_channel_io_perm_failure)
+		return PCI_ERS_RESULT_DISCONNECT;
+
 	if (netif_running(netdev))
 		ixgb_down(adapter, true);