target/linux/config: allow for selecting xtables support as module

Signed-off-by: Phil Sutter <phil@nwl.cc>

mk/modules.mk

@@ -424,6 +424,11 @@ $(eval $(call KMOD_template,BRIDGE_EBT_REDIRECT,bridge-ebt-redirect,\
 # Netfilter Core
 #
 
+$(eval $(call KMOD_template,NETFILTER_XTABLES,netfilter-xtables,\
+	$(MODULES_DIR)/kernel/net/netfilter/x_tables \
+	$(MODULES_DIR)/kernel/net/netfilter/xt_tcpudp \
+,41))
+
 $(eval $(call KMOD_template,NETFILTER_XT_TARGET_CLASSIFY,netfiler-xt-target-classify,\
 	$(MODULES_DIR)/kernel/net/netfilter/xt_CLASSIFY \
 ,50))

target/linux/config/Config.in.netfilter

@@ -16,7 +16,7 @@ config ADK_KERNEL_BRIDGE_NETFILTER
 	default n
 
 config ADK_KERNEL_NETFILTER_XTABLES
-	boolean
+	tristate "Netfilter Xtables support (required for ip_tables)"
 	select ADK_KERNEL_NETFILTER
 	select ADK_KERNEL_NETFILTER_ADVANCED
 	default y if ADK_PACKAGE_IPTABLES