drm/amd/display: Raise DPG height during timing synchronization

[Why]
Underflow counter increases in AGM when performing some mode switches due
to timing sync, which is a known hardware issue.

[How]
Temporarily raise DPG height during timing sync so that underflow is not
reported.

Signed-off-by: Taimur Hassan <syed.hassan@amd.com>
Acked-by: Aurabindo Pillai <aurabindo.pillai@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>

drivers/gpu/drm/amd/display/dc/inc/hw/opp.h

@@ -313,6 +313,11 @@ struct opp_funcs {
 			int height,
 			int offset);
 
+	void (*opp_program_dpg_dimensions)(
+				struct output_pixel_processor *opp,
+				int width,
+				int height);
+
 	bool (*dpg_is_blanked)(
 			struct output_pixel_processor *opp);