[NET]: Fix sparse warnings

Of this type, mostly:

CHECK   net/ipv6/netfilter.c
net/ipv6/netfilter.c:96:12: warning: symbol 'ipv6_netfilter_init' was not declared. Should it be static?
net/ipv6/netfilter.c:101:6: warning: symbol 'ipv6_netfilter_fini' was not declared. Should it be static?

Signed-off-by: Arnaldo Carvalho de Melo <acme@mandriva.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/include/net/udp.h b/include/net/udp.h
index ac229b7..107b9d7 100644
--- a/include/net/udp.h
+++ b/include/net/udp.h
@@ -94,6 +94,11 @@
 	struct seq_operations	seq_ops;
 };
 
+#ifdef CONFIG_PROC_FS
 extern int udp_proc_register(struct udp_seq_afinfo *afinfo);
 extern void udp_proc_unregister(struct udp_seq_afinfo *afinfo);
+
+extern int  udp4_proc_init(void);
+extern void udp4_proc_exit(void);
+#endif
 #endif	/* _UDP_H */