tcp: move struct tcp_ifcap declaration under _KERNEL

Reviewed by:		rscheff, tuexen, kib
Differential Revision:	https://reviews.freebsd.org/D44340

sys/netinet/tcp_var.h

@@ -895,17 +895,6 @@ struct hc_metrics_lite {	/* must stay in sync with hc_metrics */
 	uint32_t	rmx_recvpipe;   /* inbound delay-bandwidth product */
 };
 
-/*
- * Used by tcp_maxmtu() to communicate interface specific features
- * and limits at the time of connection setup.
- */
-struct tcp_ifcap {
-	int	ifcap;
-	u_int	tsomax;
-	u_int	tsomaxsegcount;
-	u_int	tsomaxsegsize;
-};
-
 #ifndef _NETINET_IN_PCB_H_
 struct in_conninfo;
 #endif /* _NETINET_IN_PCB_H_ */
@@ -1438,8 +1427,19 @@ extern int32_t tcp_attack_on_turns_on_logging;
 extern uint32_t tcp_ack_war_time_window;
 extern uint32_t tcp_ack_war_cnt;
 
+/*
+ * Used by tcp_maxmtu() to communicate interface specific features
+ * and limits at the time of connection setup.
+ */
+struct tcp_ifcap {
+	int	ifcap;
+	u_int	tsomax;
+	u_int	tsomaxsegcount;
+	u_int	tsomaxsegsize;
+};
 uint32_t tcp_maxmtu(struct in_conninfo *, struct tcp_ifcap *);
 uint32_t tcp_maxmtu6(struct in_conninfo *, struct tcp_ifcap *);
+
 void	 tcp6_use_min_mtu(struct tcpcb *);
 u_int	 tcp_maxseg(const struct tcpcb *);
 u_int	 tcp_fixed_maxseg(const struct tcpcb *);