Documentation/bpf: Use valid and new links in index.rst

There exists an error "404 Not Found" when I click the html link of
"Documentation/networking/filter.rst" in the BPF documentation [1],
fix it.

Additionally, use the new links about "BPF and XDP Reference Guide"
and "bpf(2)" to avoid redirects.

[1] https://www.kernel.org/doc/html/latest/bpf/

Fixes: d9b9170a2653 ("docs: bpf: Rename README.rst to index.rst")
Fixes: cb3f0d56e153 ("docs: networking: convert filter.txt to ReST")
Signed-off-by: Tiezhu Yang <[email protected]>
Signed-off-by: Daniel Borkmann <[email protected]>
Link: https://lore.kernel.org/bpf/[email protected]

0 files changed, 0 insertions, 0 deletions