iavf: rename functions and structs to new name

This basically begins the internal portion of the rename of i40evf to iavf,
by renaming many of the functions, structs, variables and defines.

Most of the changes were made mechanically, which introduces some
alignment issues.

Signed-off-by: Jesse Brandeburg <jesse.brandeburg@intel.com>
Tested-by: Andrew Bowers <andrewx.bowers@intel.com>
Signed-off-by: Jeff Kirsher <jeffrey.t.kirsher@intel.com>