i40e: add XDP support for pass and drop actions

This commit adds basic XDP support for i40e derived NICs. All XDP
actions will end up in XDP_DROP.

Signed-off-by: Björn Töpel <bjorn.topel@intel.com>
Tested-by: Andrew Bowers <andrewx.bowers@intel.com>
Signed-off-by: Jeff Kirsher <jeffrey.t.kirsher@intel.com>