sock_map: Update sock type checks for UDP

Now UDP supports sockmap and redirection, we can safely update
the sock type checks for it accordingly.

Signed-off-by: Cong Wang <cong.wang@bytedance.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Acked-by: John Fastabend <john.fastabend@gmail.com>
Link: https://lore.kernel.org/bpf/20210331023237.41094-15-xiyou.wangcong@gmail.com