[NETFILTER]: nf_conntrack: split out the event cache

This patch splits out the event cache into its own file
nf_conntrack_ecache.c

Signed-off-by: Martin Josefsson <gandalf@wlug.westbo.se>
Signed-off-by: Patrick McHardy <kaber@trash.net>
diff --git a/net/netfilter/Makefile b/net/netfilter/Makefile
index 2363764..fd0641d 100644
--- a/net/netfilter/Makefile
+++ b/net/netfilter/Makefile
@@ -1,5 +1,7 @@
 netfilter-objs := core.o nf_log.o nf_queue.o nf_sockopt.o
-nf_conntrack-objs	:= nf_conntrack_core.o nf_conntrack_standalone.o nf_conntrack_expect.o nf_conntrack_helper.o nf_conntrack_l3proto_generic.o nf_conntrack_proto_generic.o nf_conntrack_proto_tcp.o nf_conntrack_proto_udp.o
+
+nf_conntrack-y	:= nf_conntrack_core.o nf_conntrack_standalone.o nf_conntrack_expect.o nf_conntrack_helper.o nf_conntrack_l3proto_generic.o nf_conntrack_proto_generic.o nf_conntrack_proto_tcp.o nf_conntrack_proto_udp.o
+nf_conntrack-$(CONFIG_NF_CONNTRACK_EVENTS) += nf_conntrack_ecache.o
 
 obj-$(CONFIG_NETFILTER) = netfilter.o