Merge branch 'bpf-sk-msg-peek'

John Fastabend says:

====================
This adds support for the MSG_PEEK flag when redirecting into
an ingress psock sk_msg queue.

The first patch adds some base support to the helpers, then the
feature, and finally we add an option for the test suite to do
a duplicate MSG_PEEK call on every recv to test the feature.

With duplicate MSG_PEEK call all tests continue to PASS.
====================

Acked-by: Alexei Starovoitov <ast@kernel.org>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>