i40e: AQ Add external power class to get link status

Add the new External Device Power Ability field to the get_link_status data
structure, using space from the reserved field at the end of the struct.

Signed-off-by: Shannon Nelson <shannon.nelson@intel.com>
Acked-by: Kevin Scott <kevin.c.scott@intel.com>
Tested-by: Andrew Bowers <andrewx.bowers@intel.com>
Signed-off-by: Jeff Kirsher <jeffrey.t.kirsher@intel.com>