bpf, docs: Update some of the JIT/maintenance entries

Various minor updates around some of the BPF-related entries:

JITs for ARM32/NFP/SPARC/X86-32 haven't seen updates in quite a while, thus
for now, mark them as 'Odd Fixes' until they become more actively developed.

JITs for POWERPC/S390 are in good shape and receive active development and
review, thus bump to 'Supported' similar as we have with X86-64/ARM64.

JITs for MIPS/RISC-V are in similar good shape as the ones mentioned above,
but looked after mostly in spare time, thus leave for now in 'Maintained' state.

Add Michael to PPC JIT given he's picking up the patches there, so it better
reflects today's state.

Also, I haven't done much reviewing around BPF sockmap/kTLS after John and I
did the big rework back in the days to integrate sockmap with kTLS.

These days, most of this is taken care by John, Jakub {Sitnicki,Kicinski} and
others in the community, so remove myself from these two.

Lastly, move all BPF-related entries into one place, that is, move the sockmap
one over near rest of BPF.

Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Acked-by: Andrii Nakryiko <andrii@kernel.org>
Acked-by: Alexei Starovoitov <ast@kernel.org>
Acked-by: John Fastabend <john.fastabend@gmail.com>
Link: https://lore.kernel.org/r/f9b8a63a0b48dc764bd4c50f87632889f5813f69.1655494758.git.daniel@iogearbox.net
Signed-off-by: Alexei Starovoitov <ast@kernel.org>