tcp: Remove unused tcpct declarations and comments

Remove declaration, 4 defines and confusing comment that are no longer used
since 1a2c6181c4 ("tcp: Remove TCPCT").

Signed-off-by: Dmitry Popov <dp@highloadlab.com>
Acked-by: Christoph Paasch <christoph.paasch@uclouvain.be>
Signed-off-by: David S. Miller <davem@davemloft.net>

include/linux/tcp.h

@@ -107,7 +107,6 @@ static inline void tcp_clear_options(struct tcp_options_received *rx_opt)
  * only four options will fit in a standard TCP header */
 #define TCP_NUM_SACKS 4
 
-struct tcp_cookie_values;
 struct tcp_request_sock_ops;
 
 struct tcp_request_sock {

include/net/tcp.h

@@ -192,10 +192,6 @@ extern void tcp_time_wait(struct sock *sk, int state, int timeo);
 #define TCPOLEN_TIMESTAMP      10
 #define TCPOLEN_MD5SIG         18
 #define TCPOLEN_EXP_FASTOPEN_BASE  4
-#define TCPOLEN_COOKIE_BASE    2	/* Cookie-less header extension */
-#define TCPOLEN_COOKIE_PAIR    3	/* Cookie pair header extension */
-#define TCPOLEN_COOKIE_MIN     (TCPOLEN_COOKIE_BASE+TCP_COOKIE_MIN)
-#define TCPOLEN_COOKIE_MAX     (TCPOLEN_COOKIE_BASE+TCP_COOKIE_MAX)
 
 /* But this is what stacks really send out. */
 #define TCPOLEN_TSTAMP_ALIGNED		12

net/ipv4/tcp.c

@@ -410,10 +410,6 @@ void tcp_init_sock(struct sock *sk)
 
 	icsk->icsk_sync_mss = tcp_sync_mss;
 
-	/* Presumed zeroed, in order of appearance:
-	 *	cookie_in_always, cookie_out_never,
-	 *	s_data_constant, s_data_in, s_data_out
-	 */
 	sk->sk_sndbuf = sysctl_tcp_wmem[1];
 	sk->sk_rcvbuf = sysctl_tcp_rmem[1];