Add control interface

* add libosmoctrl dependency
* bind control interface

Change-Id: I4637e88da00bac1ab0237c29ac73806d024863ba
diff --git a/include/osmocom/iuh/hnbgw.h b/include/osmocom/iuh/hnbgw.h
index 58bdab4..971ede4 100644
--- a/include/osmocom/iuh/hnbgw.h
+++ b/include/osmocom/iuh/hnbgw.h
@@ -129,7 +129,7 @@
 	struct llist_head ue_list;
 	/* next availble UE Context ID */
 	uint32_t next_ue_ctx_id;
-
+	struct ctrl_handle *ctrl;
 	/* currently active CN links for CS and PS */
 	struct {
 		struct osmo_sccp_instance *client;