tcp/dccp: tw_timer_handler() is static

tw_timer_handler() is only used from net/ipv4/inet_timewait_sock.c

Fixes: 789f558c ("tcp/dccp: get rid of central timewait timer")
Signed-off-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

net/ipv4/inet_timewait_sock.c

@@ -170,7 +170,7 @@ void __inet_twsk_hashdance(struct inet_timewait_sock *tw, struct sock *sk,
 }
 EXPORT_SYMBOL_GPL(__inet_twsk_hashdance);
 
-void tw_timer_handler(unsigned long data)
+static void tw_timer_handler(unsigned long data)
 {
 	struct inet_timewait_sock *tw = (struct inet_timewait_sock *)data;