[NETFILTER]: net/ipv[46]/netfilter.c cleanups

Don't wrap entire file in #ifdef CONFIG_NETFILTER, remove a few
unneccessary includes.

Signed-off-by: Patrick McHardy <kaber@trash.net>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/include/linux/netfilter_ipv6.h b/include/linux/netfilter_ipv6.h
index 53b2983..14f2bd0 100644
--- a/include/linux/netfilter_ipv6.h
+++ b/include/linux/netfilter_ipv6.h
@@ -72,7 +72,12 @@
 	NF_IP6_PRI_LAST = INT_MAX,
 };
 
+#ifdef CONFIG_NETFILTER
 extern int ipv6_netfilter_init(void);
 extern void ipv6_netfilter_fini(void);
+#else /* CONFIG_NETFILTER */
+static inline int ipv6_netfilter_init(void) { return 0; }
+static inline void ipv6_netfilter_fini(void) { return; }
+#endif /* CONFIG_NETFILTER */
 
 #endif /*__LINUX_IP6_NETFILTER_H*/