bsc: Allow to have a list of MSCs/MUXs to connect to

Be able to configure a list of destinations (duplicates allowed)
that will be tried in a round robin fashion. The change is in
the bsc_msc_connection to operate on a list. We achieve the
round robin nature with the same trick used in the paging code
to delete and append the current entry. The nat code was updated
to compile but one can only configure one destination.
diff --git a/openbsc/include/openbsc/bsc_nat.h b/openbsc/include/openbsc/bsc_nat.h
index 8d552e2..8fbed5b 100644
--- a/openbsc/include/openbsc/bsc_nat.h
+++ b/openbsc/include/openbsc/bsc_nat.h
@@ -1,6 +1,6 @@
 /*
- * (C) 2010 by Holger Hans Peter Freyther <zecke@selfish.org>
- * (C) 2010 by On-Waves
+ * (C) 2010-2011 by Holger Hans Peter Freyther <zecke@selfish.org>
+ * (C) 2010-2011 by On-Waves
  * All Rights Reserved
  *
  * This program is free software; you can redistribute it and/or modify
@@ -236,8 +236,8 @@
 	int mgcp_length;
 
 	/* msc things */
-	char *msc_ip;
-	int msc_port;
+	struct llist_head dests;
+	struct bsc_msc_dest *main_dest;
 	struct bsc_msc_connection *msc_con;
 	char *token;