Merge branch 'bpf-uapi-doc-fixes'

Quentin Monnet says:

====================
Another round of fixes for the doc in the BPF UAPI header, which can be
turned into a manual page. First patch is the most important, as it fixes
parsing for the bpf_strtoul() helper doc. Following patches are formatting
fixes (nitpicks, mostly). The last one updates the copy of the header,
located under tools/.
====================

Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>