Merge branch 'bpf-sockmap-selftests'

John Fastabend says:

====================
This series moves ./samples/sockmap into BPF selftests. There are a
few good reasons to do this. First, by pushing this into selftests
the tests will be run automatically. Second, sockmap was not really
a sample of anything anymore, but rather a large set of tests.

Note: There are three recent fixes outstanding against bpf branch
that can be detected occasionally by the automated tests here.

https://patchwork.ozlabs.org/patch/903138/
https://patchwork.ozlabs.org/patch/903139/
https://patchwork.ozlabs.org/patch/903140/


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

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