hnbgw: move vty commands out to new hnbgw_vty.c

Pass g_hnb_gw and tall_hnb_ctx to hnbgw_vty_init() as they are no longer
statically available.

Change-Id: If85c1b97a240bd1dcf9f367ea6fca857d542ab22
diff --git a/src/hnbgw.h b/src/hnbgw.h
index 9f010d9..9b5ae85 100644
--- a/src/hnbgw.h
+++ b/src/hnbgw.h
@@ -132,6 +132,8 @@
 	struct hnbgw_cnlink *cnlink_ps;
 };
 
+extern void *talloc_asn1_ctx;
+
 struct ue_context *ue_context_by_id(struct hnb_gw *gw, uint32_t id);
 struct ue_context *ue_context_by_imsi(struct hnb_gw *gw, const char *imsi);
 struct ue_context *ue_context_alloc(struct hnb_context *hnb, const char *imsi);
@@ -139,3 +141,5 @@
 
 struct hnb_context *hnb_context_alloc(struct hnb_gw *gw, struct osmo_stream_srv_link *link, int new_fd);
 void hnb_context_release(struct hnb_context *ctx);
+
+void hnbgw_vty_init(struct hnb_gw *gw, void *tall_ctx);