drm/amd/display: add a override flag as wa for some specific dongle

[Why & How]
Add a override flag as wa for some specific dongle
Co-authored-by: Leo Chen <sancchen@amd.com>
Reviewed-by: Charlene Liu <Charlene.Liu@amd.com>
Acked-by: Brian Chang <Brian.Chang@amd.com>
Signed-off-by: Leo Chen <SanChuan.Chen@amd.com>
Tested-by: Daniel Wheeler <daniel.wheeler@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>

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

@@ -224,6 +224,7 @@ struct dc_link {
 		bool dpia_mst_dsc_always_on;
 		/* Forced DPIA into TBT3 compatibility mode. */
 		bool dpia_forced_tbt3_mode;
+		bool dongle_mode_timing_override;
 	} wa_flags;
 	struct link_mst_stream_allocation_table mst_stream_alloc_table;