Merge branch 'bpf-sock-hashmap'

John Fastabend says:

====================
In the original sockmap implementation we got away with using an
array similar to devmap. However, unlike devmap where an ifindex
has a nice 1:1 function into the map we have found some use cases
with sockets that need to be referenced using longer keys.

This series adds support for a sockhash map reusing as much of
the sockmap code as possible. I made the decision to add sockhash
specific helpers vs trying to generalize the existing helpers
because (a) they have sockmap in the name and (b) the keys are
different types. I prefer to be explicit here rather than play
type games or do something else tricky.

To test this we duplicate all the sockmap testing except swap out
the sockmap with a sockhash.

v2: fix file stats and add v2 tag
v3: move tool updates into test patch, move bpftool updates into
    its own patch, and fixup the test patch stats to catch the
    renamed file and provide only diffs ± on that.
v4: Add documentation to UAPI bpf.h
v5: Add documentation to tools UAPI bpf.h
v6: 'git add' test_sockhash_kern.c which was previously missing
    but was not causing issues because of typo in test script,
    noticed by Daniel. After this the git format-patch -M option
    no longer tracks the rename of the test_sockmap_kern files for
    some reason. I guess the diff has exceeded some threshold.
====================

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