Merge branch 'fix-bpf-helpers-doc'

Andrey Ignatov says:

====================
BPF helpers documentation in UAPI refers to kernel ctx structures when it
has to refer to user visible ones. Fix it.
====================

Reviewed-by: Quentin Monnet <quentin.monnet@netronome.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>