netfilter: xt_rpfilter: depend on raw or mangle table

rpfilter is only valid in raw/mangle PREROUTING, i.e.
RPFILTER=y|m is useless without raw or mangle table support.
Signed-off-by: Florian Westphal <fw@strlen.de>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

net/ipv4/netfilter/Kconfig

@@ -71,7 +71,7 @@ config IP_NF_MATCH_ECN
 
 config IP_NF_MATCH_RPFILTER
 	tristate '"rpfilter" reverse path filter match support'
-	depends on NETFILTER_ADVANCED
+	depends on NETFILTER_ADVANCED && (IP_NF_MANGLE || IP_NF_RAW)
 	---help---
 	  This option allows you to match packets whose replies would
 	  go out via the interface the packet came in.

net/ipv6/netfilter/Kconfig

@@ -105,7 +105,7 @@ config IP6_NF_MATCH_MH
 
 config IP6_NF_MATCH_RPFILTER
 	tristate '"rpfilter" reverse path filter match support'
-	depends on NETFILTER_ADVANCED
+	depends on NETFILTER_ADVANCED && (IP6_NF_MANGLE || IP6_NF_RAW)
 	---help---
 	  This option allows you to match packets whose replies would
 	  go out via the interface the packet came in.