bpf, udp: Remove some pointless comments

These comments in udp_bpf_update_proto() are copied from the
original TCP code and apparently do not apply to UDP. Just
remove them.
Reported-by: Jakub Sitnicki <jakub@cloudflare.com>
Signed-off-by: Cong Wang <cong.wang@bytedance.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Acked-by: John Fastabend <john.fastabend@gmail.com>
Link: https://lore.kernel.org/bpf/20210403052715.13854-1-xiyou.wangcong@gmail.com

net/ipv4/udp_bpf.c

@@ -110,7 +110,6 @@ int udp_bpf_update_proto(struct sock *sk, bool restore)
 
 	if (restore) {
 		sk->sk_write_space = psock->saved_write_space;
-		/* Pairs with lockless read in sk_clone_lock() */
 		WRITE_ONCE(sk->sk_prot, psock->sk_proto);
 		return 0;
 	}
@@ -118,7 +117,6 @@ int udp_bpf_update_proto(struct sock *sk, bool restore)
 	if (sk->sk_family == AF_INET6)
 		udp_bpf_check_v6_needs_rebuild(psock->sk_proto);
 
-	/* Pairs with lockless read in sk_clone_lock() */
 	WRITE_ONCE(sk->sk_prot, &udp_bpf_prots[family]);
 	return 0;
 }