net/af_xdp: fix multi interface support for K8s

The original 'use_cni' implementation, was added
to enable support for the AF_XDP PMD in a K8s env
without any escalated privileges.
However 'use_cni' used a hardcoded socket rather
than a configurable one. If a DPDK pod is requesting
multiple net devices and these devices are from
different pools, then the AF_XDP PMD attempts to
mount all the netdev UDSes in the pod as /tmp/afxdp.sock.
Which means that at best only 1 netdev will handshake
correctly with the AF_XDP DP. This patch addresses
this by making the socket parameter configurable using
a new vdev param called 'uds_path' and removing the
previous 'use_cni' param. This change has been tested
with the AF_XDP DP PR 81[1], with both single and
multiple interfaces. This patch also renames the
af_xdp_cni.rst doc to af_xdp_dp.rst and changes
incorrect references to the DP as CNI. Lastly,
this patch adds this feature to the release notes.

[1] intel/afxdp-plugins-for-kubernetes#81

Signed-off-by: Maryam Tahhan <mtahhan@redhat.com>
Reviewed-by: Ciara Loftus <ciara.loftus@intel.com>
Reviewed-by: Shibin Koikkara Reeny <shibin.koikkara.reeny@intel.com>
Signed-off-by: 0-day Robot <robot@bytheb.org>