tools: ynl: extend netdev sample to dump xdp-rx-metadata-features

The tool can be used to verify that everything works end to end.

Unrelated updates:
- include tools/include/uapi to pick the latest kernel uapi headers
- print "xdp-features" and "xdp-rx-metadata-features" so it's clear
  which bitmask is being dumped

Cc: netdev@vger.kernel.org
Cc: Willem de Bruijn <willemb@google.com>
Signed-off-by: Stanislav Fomichev <sdf@google.com>
Link: https://lore.kernel.org/r/20230913171350.369987-4-sdf@google.com


Signed-off-by: Martin KaFai Lau <martin.lau@kernel.org>