tcp: use drop reasons in cookie check for ipv4

tcp: use drop reasons in cookie check for ipv4

Now it's time to use the prepared definitions to refine this part.
Four reasons used might enough for now, I think.

Signed-off-by: Jason Xing <kernelxing@tencent.com>
Reviewed-by: Eric Dumazet <edumazet@google.com>
Reviewed-by: David Ahern <dsahern@kernel.org>
Reviewed-by: Kuniyuki Iwashima <kuniyu@amazon.com>
Signed-off-by: David S. Miller <davem@davemloft.net>