netfilter: fix warning in net/netfilter/nf_conntrack_proto_tcp.c

fix this warning:

  net/netfilter/nf_conntrack_proto_tcp.c: In function \u2018tcp_in_window\u2019:
  net/netfilter/nf_conntrack_proto_tcp.c:491: warning: unused variable \u2018net\u2019
  net/netfilter/nf_conntrack_proto_tcp.c: In function \u2018tcp_packet\u2019:
  net/netfilter/nf_conntrack_proto_tcp.c:812: warning: unused variable \u2018net\u2019

Signed-off-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Patrick McHardy <kaber@trash.net>

include/net/netfilter/nf_conntrack_l4proto.h

@@ -129,7 +129,7 @@ extern const struct nla_policy nf_ct_port_nla_policy[];
 	 && net_ratelimit())
 #endif
 #else
-#define LOG_INVALID(net, proto) 0
+static inline int LOG_INVALID(struct net *net, int proto) { return 0; }
 #endif /* CONFIG_SYSCTL */
 
 #endif /*_NF_CONNTRACK_PROTOCOL_H*/