i40e/i40evf: add exec_aq command to nvmupdate utility

Add a facility to run AQ commands through the nvmupdate utility in order
to allow the update tools to interact with the FW and do special
commands needed for updates and configuration changes.

Change-ID: I5c41523e4055b37f8e4ee479f7a0574368f4a588
Signed-off-by: Shannon Nelson <shannon.nelson@intel.com>
Tested-by: Andrew Bowers <andrewx.bowers@intel.com>
Signed-off-by: Jeff Kirsher <jeffrey.t.kirsher@intel.com>