Remove 'struct bsc_msc_connection' + fix IPA-encapsulated CTRL

The bsc_msc_connection dates back to the old pre-libosmo-sigtran
days, and 90% of the field members weren't used at all (even the
new sigtran specific ones!).  Let's merge what remains into struct
bsc_msc_data.

As a side effect, the already dysfunctional "dest A.B.C.D" VTY
command has been removed from the MSC node.

There's quite a bit of fall-out in the CTRL interface, which was
the code with strongest ties to bsc_msc_connection.  This was
resolved by properly porting CTRL handling over to libosmo-sigtran,
meaning that an IPA/SCCPlite connected MSC can now again send CTRL
GET/SET commands, and can also receive those selective few TRAPs
that old osmo-bsc-sccplite also sent to its MSC[s].

Change-Id: I6b7354f3b23a26bb4eab12213ca3d3b614c8154f
Related: OS#2012
diff --git a/include/osmocom/bsc/bsc_msc_data.h b/include/osmocom/bsc/bsc_msc_data.h
index 2ace178..baa58e7 100644
--- a/include/osmocom/bsc/bsc_msc_data.h
+++ b/include/osmocom/bsc/bsc_msc_data.h
@@ -3,6 +3,7 @@
  *
  * (C) 2010-2015 by Holger Hans Peter Freyther <zecke@selfish.org>
  * (C) 2010-2015 by On-Waves
+ * (C) 2018 by Harald Welte <laforge@gnumonks.org>
  * All Rights Reserved
  *
  * This program is free software; you can redistribute it and/or modify
@@ -27,7 +28,6 @@
 #ifndef _OSMO_MSC_DATA_H
 #define _OSMO_MSC_DATA_H
 
-#include "bsc_msc.h"
 #include "debug.h"
 
 #include <osmocom/core/timer.h>
@@ -75,26 +75,20 @@
 
 
 	/* Connection data */
-	struct bsc_msc_connection *msc_con;
 	struct osmo_plmn_id core_plmn;
 	int core_lac;
 	int core_ci;
 	int rtp_base;
+	bool is_authenticated;
 
 	/* audio codecs */
 	struct gsm48_multi_rate_conf amr_conf;
 	struct gsm_audio_support **audio_support;
 	int audio_length;
 
-	/* destinations */
-	struct llist_head dests;
-
 	/* ussd welcome text */
 	char *ussd_welcome_txt;
 
-	/* mgcp agent */
-	struct osmo_wqueue mgcp_agent;
-
 	int nr;
 
 	/* ussd msc connection lost text */