sdm: Add support for secondary vsync

Add support for enabling secondary vsync

Change-Id: Ia2231a19292314513d613efbb6953b1943530af0
CRs-fixed: 2184506
diff --git a/libdrmutils/drm_interface.h b/libdrmutils/drm_interface.h
index 97660ea..c25832c 100644
--- a/libdrmutils/drm_interface.h
+++ b/libdrmutils/drm_interface.h
@@ -1,5 +1,5 @@
 /*
-* Copyright (c) 2017, The Linux Foundation. All rights reserved.
+* Copyright (c) 2017-2018, The Linux Foundation. All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions are
@@ -498,6 +498,7 @@
 struct DRMDisplayToken {
   uint32_t conn_id;
   uint32_t crtc_id;
+  uint32_t crtc_index;
 };
 
 enum DRMPPFeatureID {