msgb talloc ctx: initialize in all main() scopes

Add msgb_talloc_ctx_init() call to many main() functions still lacking a
msgb talloc context.

Change-Id: Ib0d6751260659cabf18a7ce80680ba2fb4228ea1
diff --git a/openbsc/src/osmo-bsc_mgcp/mgcp_main.c b/openbsc/src/osmo-bsc_mgcp/mgcp_main.c
index ac55e25..964768e 100644
--- a/openbsc/src/osmo-bsc_mgcp/mgcp_main.c
+++ b/openbsc/src/osmo-bsc_mgcp/mgcp_main.c
@@ -203,6 +203,7 @@
 	int on = 1, rc;
 
 	tall_bsc_ctx = talloc_named_const(NULL, 1, "mgcp-callagent");
+	msgb_talloc_ctx_init(tall_bsc_ctx, 0);
 
 	osmo_init_ignore_signals();
 	osmo_init_logging(&log_info);