Merge branch 'libbpf: deprecate some setter and getter APIs'

Andrii Nakryiko says:

====================

Another batch of simple deprecations. One of the last few, hopefully, as we
are getting close to deprecating all the planned APIs/features. See
individual patches for details.

v1->v2:
  - rebased on latest bpf-next, fixed Closes: reference.
====================

Signed-off-by: Alexei Starovoitov <ast@kernel.org>