drm/amd/display: remove unused function

[Why]
This function is not being used, it was left in
when introducing DCN2

[How]
Remove the function
Signed-off-by: NQingqing Zhuo <qingqing.zhuo@amd.com>
Reviewed-by: NEric Bernstein <Eric.Bernstein@amd.com>
Acked-by: NBhawanpreet Lakha <Bhawanpreet.Lakha@amd.com>
Signed-off-by: NAlex Deucher <alexander.deucher@amd.com>

drivers/gpu/drm/amd/display/dc/dcn20/dcn20_opp.c

@@ -332,7 +332,6 @@ static struct opp_funcs dcn20_opp_funcs = {
 		.opp_set_disp_pattern_generator = opp2_set_disp_pattern_generator,
 		.dpg_is_blanked = opp2_dpg_is_blanked,
 		.opp_dpg_set_blank_color = opp2_dpg_set_blank_color,
-		.opp_convert_pti = NULL,
 		.opp_destroy = opp1_destroy,
 		.opp_program_left_edge_extra_pixel = opp2_program_left_edge_extra_pixel,
 };

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

@@ -316,11 +316,6 @@ struct opp_funcs {
 	bool (*dpg_is_blanked)(
 			struct output_pixel_processor *opp);
 
-	void (*opp_convert_pti)(
-		struct output_pixel_processor *opp,
-		bool enable,
-		bool polarity);
-
 	void (*opp_dpg_set_blank_color)(
 			struct output_pixel_processor *opp,
 			const struct tg_color *color);