Some symbols exported to other modules are really used only by
openvswitch.ko. Remove the exports.

Tested by loading all 4 openvswitch modules, nothing breaks.
Signed-off-by: NJiri Benc <jbenc@redhat.com>
Acked-by: NPravin B Shelar <pshelar@ovn.org>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>