Documentation: xsk: correct the obsolete references and examples

The modified lines are mainly related to the following commits[1][2]
which remove those tests and examples. Since samples/bpf has been
deprecated, we can refer to more examples that are easily searched
in the various xdp-projects, like the following link:
https://github.com/xdp-project/bpf-examples/tree/main/AF_XDP-example

[1]
commit f36600634282 ("libbpf: move xsk.{c,h} into selftests/bpf")
[2]
commit cfb5a2dbf141 ("bpf, samples: Remove AF_XDP samples")

Signed-off-by: Jason Xing <[email protected]>
Reviewed-by: Toke Høiland-Jørgensen <[email protected]>
Reviewed-by: Maciej Fijalkowski <[email protected]>
Acked-by: Stanislav Fomichev <[email protected]>
Link: https://patch.msgid.link/[email protected]
Signed-off-by: Jakub Kicinski <[email protected]>

0 files changed, 0 insertions, 0 deletions