Add required plumbing for new VSI type dedicated to devlink subfunctions.
Make sure that the vsi is properly configured and destroyed. Also allow
loading XDP and AF_XDP sockets.

The first implementation of devlink subfunctions supports only one Tx/Rx
queue pair per given subfunction.
Reviewed-by: Simon Horman <horms@kernel.org>
Reviewed-by: Przemek Kitszel <przemyslaw.kitszel@intel.com>
Reviewed-by: Wojciech Drewek <wojciech.drewek@intel.com>
Signed-off-by: Piotr Raczynski <piotr.raczynski@intel.com>
Signed-off-by: Michal Swiatkowski <michal.swiatkowski@linux.intel.com>
Tested-by: Rafal Romanowski <rafal.romanowski@intel.com>
Signed-off-by: Tony Nguyen <anthony.l.nguyen@intel.com>