Bump driver versions to i40e-1.4.12 and i40evf-1.4.8

Change-ID: I0ad82668c4ded04250391fda396ce191a42ab754
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>