drm/amd/display: remove no need return value

Functions (disable_all_writeback_pipes_for_stream &
dc_enable_stereo & dc_post_update_surfaces_to_stream)
always return true, there is no need to keep the return value.
This change is to make the code a bit more readable.
Signed-off-by: Bernard Zhao <bernard@vivo.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>

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

@@ -763,7 +763,7 @@ static bool dc_construct(struct dc *dc,
 	return false;
 }
 
-static bool disable_all_writeback_pipes_for_stream(
+static void disable_all_writeback_pipes_for_stream(
 		const struct dc *dc,
 		struct dc_stream_state *stream,
 		struct dc_state *context)
@@ -772,8 +772,6 @@ static bool disable_all_writeback_pipes_for_stream(
 
 	for (i = 0; i < stream->num_wb_info; i++)
 		stream->writeback_info[i].wb_enabled = false;
-
-	return true;
 }
 
 void apply_ctx_interdependent_lock(struct dc *dc, struct dc_state *context, struct dc_stream_state *stream, bool lock)
@@ -1269,13 +1267,12 @@ bool dc_validate_seamless_boot_timing(const struct dc *dc,
 	return true;
 }
 
-bool dc_enable_stereo(
+void dc_enable_stereo(
 	struct dc *dc,
 	struct dc_state *context,
 	struct dc_stream_state *streams[],
 	uint8_t stream_count)
 {
-	bool ret = true;
 	int i, j;
 	struct pipe_ctx *pipe;
 
@@ -1290,8 +1287,6 @@ bool dc_enable_stereo(
 				dc->hwss.setup_stereo(pipe, dc);
 		}
 	}
-
-	return ret;
 }
 
 void dc_trigger_sync(struct dc *dc, struct dc_state *context)
@@ -1530,18 +1525,18 @@ static bool is_flip_pending_in_pipes(struct dc *dc, struct dc_state *context)
 	return false;
 }
 
-bool dc_post_update_surfaces_to_stream(struct dc *dc)
+void dc_post_update_surfaces_to_stream(struct dc *dc)
 {
 	int i;
 	struct dc_state *context = dc->current_state;
 
 	if ((!dc->optimized_required) || dc->optimize_seamless_boot_streams > 0)
-		return true;
+		return;
 
 	post_surface_trace(dc);
 
 	if (is_flip_pending_in_pipes(dc, context))
-		return true;
+		return;
 
 	for (i = 0; i < dc->res_pool->pipe_count; i++)
 		if (context->res_ctx.pipe_ctx[i].stream == NULL ||
@@ -1554,8 +1549,6 @@ bool dc_post_update_surfaces_to_stream(struct dc *dc)
 
 	dc->optimized_required = false;
 	dc->wm_optimized_required = false;
-
-	return true;
 }
 
 static void init_state(struct dc *dc, struct dc_state *context)

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

@@ -963,7 +963,7 @@ struct dc_flip_addrs {
 	bool triplebuffer_flips;
 };
 
-bool dc_post_update_surfaces_to_stream(
+void dc_post_update_surfaces_to_stream(
 		struct dc *dc);
 
 #include "dc_stream.h"

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

@@ -392,7 +392,7 @@ enum dc_status dc_validate_stream(struct dc *dc, struct dc_stream_state *stream)
  * Enable stereo when commit_streams is not required,
  * for example, frame alternate.
  */
-bool dc_enable_stereo(
+void dc_enable_stereo(
 	struct dc *dc,
 	struct dc_state *context,
 	struct dc_stream_state *streams[],