i40evf: remove aq_pending

The aq_pending field in the adapter structure is actually redundant with
the current_op field. Remove the aq_pending field and expunge all traces
of it from the official record. This simplifies the code significantly,
especially in the virtual channel completion routine.

Change-ID: Ib2957c8c19882bd0cecc6fcd133912c24b46a1ff
Signed-off-by: Mitch Williams <mitch.a.williams@intel.com>
Tested-by: Jim Young <james.m.young@intel.com>
Signed-off-by: Jeff Kirsher <jeffrey.t.kirsher@intel.com>