drm/amd/display: no need for return value from ipp_program_degamma_pwl

Signed-off-by: Dmytro Laktyushkin <Dmytro.Laktyushkin@amd.com>
Acked-by: Harry Wentland <Harry.Wentland@amd.com>
Reviewed-by: Tony Cheng <Tony.Cheng@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>

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

@@ -118,7 +118,7 @@ struct ipp_funcs {
 		struct input_pixel_processor *ipp,
 		enum ipp_degamma_mode mode);
 
-	bool (*ipp_program_degamma_pwl)(
+	void (*ipp_program_degamma_pwl)(
 		struct input_pixel_processor *ipp,
 		const struct pwl_params *params);