igb: do a reset on SR-IOV re-init if device is down

commit 76252723 upstream.

To properly re-initialize SR-IOV it is necessary to reset the device
even if it is already down. Not doing this may result in Tx unit hangs.
Signed-off-by: Stefan Assmann <sassmann@kpanic.de>
Tested-by: Aaron Brown <aaron.f.brown@intel.com>
Signed-off-by: Jeff Kirsher <jeffrey.t.kirsher@intel.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>

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

@@ -6610,6 +6610,8 @@ static int __igb_shutdown(struct pci_dev *pdev, bool *enable_wake)
 
 	if (netif_running(netdev))
 		igb_close(netdev);
+	else
+		igb_reset(adapter);
 
 	igb_clear_interrupt_scheme(adapter);