iavf: rename i40e_status to iavf_status

This is just a rename of an internal variable i40e_status, but
it was a pretty big change and so deserved it's own patch.

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>