mgcp_trunk: use talloc_zero_array instead of _talloc_zero_array

_talloc_zero_array is not supposed to be called by the API user. Lets
use talloc_zero_array instead.

Related: OS#2659
Change-Id: I27549585016a7998e9233c52f6d86429fc75f509
diff --git a/src/libosmo-mgcp/mgcp_trunk.c b/src/libosmo-mgcp/mgcp_trunk.c
index 55a8953..0d7b385 100644
--- a/src/libosmo-mgcp/mgcp_trunk.c
+++ b/src/libosmo-mgcp/mgcp_trunk.c
@@ -101,8 +101,8 @@
 	OSMO_ASSERT(number_endpoints < 65534);
 
 	/* allocate pointer array for the endpoints */
-	trunk->endpoints = _talloc_zero_array(trunk->cfg,
-					      sizeof(struct mgcp_endpoint *), number_endpoints, "endpoints");
+	trunk->endpoints = talloc_zero_array(trunk->cfg, struct mgcp_endpoint*,
+					     number_endpoints);
 	if (!trunk->endpoints)
 		return -1;