mgcp: Introduce a trunk config for multiple trunks.

A trunk will always have 32 endpoints to be used and we allow
a sparse allocation of endpoints.
diff --git a/openbsc/include/openbsc/mgcp_internal.h b/openbsc/include/openbsc/mgcp_internal.h
index cefbc3e..7c6bb54 100644
--- a/openbsc/include/openbsc/mgcp_internal.h
+++ b/openbsc/include/openbsc/mgcp_internal.h
@@ -147,5 +147,8 @@
 	return endpoint + 60;
 }
 
+struct mgcp_trunk_config *mgcp_trunk_alloc(struct mgcp_config *cfg, int index);
+struct mgcp_trunk_config *mgcp_trunk_num(struct mgcp_config *cfg, int index);
+
 
 #endif