i40e: keep service tasks out of reset process

Make sure the service tasks don't try to meddle with the
device while a reset is in progress.  Odd things can happen
such as funky stats values.

Change-ID: I6929cb9d6d96839c9279362ca7c0e3fe6c8fcc66
Signed-off-by: Shannon Nelson <shannon.nelson@intel.com>
Signed-off-by: Jeff Kirsher <jeffrey.t.kirsher@intel.com>