Revert "net: correct sk_acceptq_is_full()"

Revert "net: correct sk_acceptq_is_full()"

This reverts commit cf1f1a4f9627ae1d290d459762b2ed43740d8b46.

We had similar attempt in the past, and we reverted it.

History:

13ed5242336140b98da26643a45bc292e44a520f [NET]: Revert incorrect accept queue backlog changes.
dddaf2f9c82ba2e165fc55c3970a28ece28da28f [NET]: Fix bugs in "Whether sock accept queue is full" checking

I am adding a fat comment so that future attempts will
be much harder.

Fixes: cf1f1a4f9627 ("net: correct sk_acceptq_is_full()")
Cc: iuyacan <yacanliu@163.com>
Signed-off-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>