i40evf: Don't schedule reset_task when device is being removed

When a host disables and enables a PF device, all the associated
VFs are removed and added back in. It also generates a PFR which in turn
resets all the connected VFs. This behaviour is different from that of
Linux guest on Linux host. Hence we end up in a situation where there's
a PFR and device removal at the same time. And watchdog doesn't have a
clue about this and schedules a reset_task. This patch adds code to send
signal to reset_task that the device is currently being removed.

Signed-off-by: Avinash Dayanand <avinash.dayanand@intel.com>
Tested-by: Andrew Bowers <andrewx.bowers@intel.com>
Signed-off-by: Jeff Kirsher <jeffrey.t.kirsher@intel.com>