i40e/i40evf: Add base address registers to aq struct

Add the Base Address High and Low to the admin queue struct to simplify
another bit of "which context" logic in the config routines.

Change-ID: Iae195a7da3baffc1a9d522119e1e2b427068ad07
Signed-off-by: Shannon Nelson <shannon.nelson@intel.com>
Signed-off-by: Jeff Kirsher <jeffrey.t.kirsher@intel.com>