idpf: implement Rx path for AF_XDP

Implement Rx packet processing specific to AF_XDP ZC using the libeth
XSk infra. Initialize queue registers before allocating buffers to
avoid redundant ifs when updating the queue tail.

Co-developed-by: Michal Kubiak <michal.kubiak@intel.com>
Signed-off-by: Michal Kubiak <michal.kubiak@intel.com>
Signed-off-by: Alexander Lobakin <aleksander.lobakin@intel.com>
Tested-by: Ramu R <ramu.r@intel.com>
Signed-off-by: Tony Nguyen <anthony.l.nguyen@intel.com>