af_packet: match_fanout_group() can be static

cc: Eric Leblond <eric@regit.org>
Signed-off-by: NFengguang Wu <fengguang.wu@intel.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

net/packet/af_packet.c

@@ -1273,7 +1273,7 @@ static void __fanout_unlink(struct sock *sk, struct packet_sock *po)
 	spin_unlock(&f->lock);
 }
 
-bool match_fanout_group(struct packet_type *ptype, struct sock * sk)
+static bool match_fanout_group(struct packet_type *ptype, struct sock * sk)
 {
 	if (ptype->af_packet_priv == (void*)((struct packet_sock *)sk)->fanout)
 		return true;