bpf: Enable perf event rb output for bpf cgroup progs

bpf: Enable perf event rb output for bpf cgroup progs

Currently, connect(), sendmsg(), recvmsg() and bind-related hooks
are all lacking perf event rb output in order to push notifications
or monitoring events up to user space. Back in commit a5a3a828cd00
("bpf: add perf event notificaton support for sock_ops"), I've worked
with Sowmini to enable them for sock_ops where the context part is
not used (as opposed to skbs for example where the packet data can
be appended). Make the bpf_sockopt_event_output() helper generic and
enable it for mentioned hooks.

Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Link: https://lore.kernel.org/bpf/69c39daf87e076b31e52473c902e9bfd37559124.1585323121.git.daniel@iogearbox.net