samples/bpf: Update cgrp2 socket tests

Update cgrp2 bpf sock tests to check that device, mark and priority
can all be set on a socket via bpf programs attached to a cgroup.

Signed-off-by: David Ahern <dsahern@gmail.com>
Acked-by: Alexei Starovoitov <ast@kernel.org>
Signed-off-by: David S. Miller <davem@davemloft.net>