bpf, doc: Add arm32 as arch supporting eBPF JIT

As eBPF JIT support for arm32 was added recently with
commit 39c13c20, it seems appropriate to
add arm32 as arch with support for eBPF JIT in bpf and sysctl docs as well.

Signed-off-by: Shubham Bansal <illusionist.neo@gmail.com>
Acked-by: Alexei Starovoitov <ast@kernel.org>
Acked-by: Daniel Borkmann <daniel@iogearbox.net>
Signed-off-by: David S. Miller <davem@davemloft.net>