net/sched: Export tc_tunnel_key so its UAPI accessible

Export tc_tunnel_key so it can be used from user space.

Signed-off-by: Roi Dayan <roid@mellanox.com>
Reviewed-by: Amir Vadai <amir@vadai.me>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/include/uapi/linux/tc_act/Kbuild b/include/uapi/linux/tc_act/Kbuild
index e3969bd..9611c7b 100644
--- a/include/uapi/linux/tc_act/Kbuild
+++ b/include/uapi/linux/tc_act/Kbuild
@@ -11,3 +11,4 @@
 header-y += tc_bpf.h
 header-y += tc_connmark.h
 header-y += tc_ife.h
+header-y += tc_tunnel_key.h