netfilter: reduce NF_MAX_HOOKS define

This can be same as NF_INET_NUMHOOKS if we don't support DECNET.
Signed-off-by: Florian Westphal <fw@strlen.de>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

include/linux/netfilter_defs.h

@@ -4,13 +4,17 @@
 
 #include <uapi/linux/netfilter.h>
 
-/* Largest hook number + 1, see uapi/linux/netfilter_decnet.h */
-#define NF_MAX_HOOKS 8
-
 /* in/out/forward only */
 #define NF_ARP_NUMHOOKS 3
 
 /* max hook is NF_DN_ROUTE (6), also see uapi/linux/netfilter_decnet.h */
 #define NF_DN_NUMHOOKS 7
 
+#if IS_ENABLED(CONFIG_DECNET)
+/* Largest hook number + 1, see uapi/linux/netfilter_decnet.h */
+#define NF_MAX_HOOKS	NF_DN_NUMHOOKS
+#else
+#define NF_MAX_HOOKS	NF_INET_NUMHOOKS
+#endif
+
 #endif