drm/amd/display: Add debug option to disable timing sync

[Why]
We want a debug option to disable timing sync for testing.

[How]
New dc debug option that must be false to call program_timing_sync
Signed-off-by: Joshua Aberback <joshua.aberback@amd.com>
Reviewed-by: Jun Lei <Jun.Lei@amd.com>
Acked-by: Leo Li <sunpeng.li@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>

drivers/gpu/drm/amd/display/dc/core/dc.c

@@ -1062,7 +1062,7 @@ static enum dc_status dc_commit_state_no_check(struct dc *dc, struct dc_state *c
 	if (result != DC_OK)
 		return result;
 
-	if (context->stream_count > 1) {
+	if (context->stream_count > 1 && !dc->debug.disable_timing_sync) {
 		enable_timing_multisync(dc, context);
 		program_timing_sync(dc, context);
 	}

drivers/gpu/drm/amd/display/dc/dc.h

@@ -378,6 +378,7 @@ struct dc_debug_options {
 	 * watermarks are not affected.
 	 */
 	unsigned int force_min_dcfclk_mhz;
+	bool disable_timing_sync;
 };
 
 struct dc_debug_data {