i40evf: don't stop watchdog if it hasn't started

If the VF driver fails to complete early init, then rmmod can cause a
softlock when the driver tries to stop a watchdog timer that never even
got initialized.

Add a check to see if the timer is actually initialized before stopping
it.

Change-ID: Id9d550aa8838e07f4b02afe7bc017ef983779efc
Signed-off-by: Mitch Williams <mitch.a.williams@intel.com>
Signed-off-by: Jeff Kirsher <jeffrey.t.kirsher@intel.com>

drivers/net/ethernet/intel/i40evf/i40evf_main.c

@@ -2408,7 +2408,9 @@ static void i40evf_remove(struct pci_dev *pdev)
 		i40evf_reset_interrupt_capability(adapter);
 	}
 
-	del_timer_sync(&adapter->watchdog_timer);
+	if (adapter->watchdog_timer.function)
+		del_timer_sync(&adapter->watchdog_timer);
+
 	flush_scheduled_work();
 
 	if (hw->aq.asq.count)