e1000: return PCI_ERS_RESULT_DISCONNECT on permanent error

PCI drivers that implement the io_error_detected callback
should return PCI_ERS_RESULT_DISCONNECT if the state
passed in is pci_channel_io_perm_failure.  This state is
not checked in many of the network drivers.

The patch fixes the omission in the e1000 driver.

Based on Mike Mason's similar patch for e1000e.
Signed-off-by: Andre Detsch <adetsch@br.ibm.com>
CC: Mike Mason <mmlnx@us.ibm.com>
Signed-off-by: Jeff Kirsher <jeffrey.t.kirsher@intel.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

drivers/net/e1000/e1000_main.c

@@ -4823,6 +4823,9 @@ static pci_ers_result_t e1000_io_error_detected(struct pci_dev *pdev,
 
 	netif_device_detach(netdev);
 
+	if (state == pci_channel_io_perm_failure)
+		return PCI_ERS_RESULT_DISCONNECT;
+
 	if (netif_running(netdev))
 		e1000_down(adapter);
 	pci_disable_device(pdev);