openvswitch: conditionally depends on nf_conncount.ko

This is required for conntrack zone limit support.  Linux upstream
commit is 11efd5cb ("openvswitch: Support conntrack zone limit")

Ref: https://github.com/openwrt/packages/issues/9274#issuecomment-507181166
Reported-by: Lech Perczak <lech.perczak@gmail.com>
Signed-off-by: Yousong Zhou <yszhou4tech@gmail.com>

net/openvswitch/Makefile

@@ -16,7 +16,7 @@ include $(INCLUDE_DIR)/kernel.mk
 #
 PKG_NAME:=openvswitch
 PKG_VERSION:=2.11.1
-PKG_RELEASE:=1
+PKG_RELEASE:=2
 PKG_SOURCE:=$(PKG_NAME)-$(PKG_VERSION).tar.gz
 PKG_SOURCE_URL:=https://www.openvswitch.org/releases/
 PKG_HASH:=c1296ae44a7b176150915e33bc497cc0a7a02caeba84ea43ce9b6a2509d9b5dc
@@ -75,6 +75,7 @@ ovs_kmod_openvswitch_depends:=\
 	  +kmod-nf-conntrack \
 	  +IPV6:kmod-nf-conntrack6 \
 	  +(!LINUX_4_9&&!LINUX_4.14):kmod-nsh \
+	  +(!LINUX_4_9&&!LINUX_4.14):kmod-ipt-conntrack-extra \
 
 ovs_kmod_openvswitch_files:=$(ovs_kmod_upstream_dir)/openvswitch.ko
 $(eval $(call OvsKmodPackageTemplate,openvswitch))