drm/amd/display: After program backend, also program front end regs.

Issue:
In case of two 4K@60 + one non-4k monitor, when unplug non-4k monitor,
the remain two 4k monitor don't work properly.
Reason:
In that case, two 4k use two pipes and no split, when unplug happens,
those two monitor will use 4 pipes and split, but on that time, frontend
is not programed properly.
Solution:
After programed backend, front end should be programmed as per new pipe
setting.
Signed-off-by: Yongqiang Sun <yongqiang.sun@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/core/dc.c

@@ -806,7 +806,7 @@ bool dc_commit_streams(
 	enum dc_status result = DC_ERROR_UNEXPECTED;
 	struct validate_context *context;
 	struct dc_validation_set set[MAX_STREAMS] = { {0, {0} } };
-	int i, j, k;
+	int i, j;
 
 	if (false == streams_changed(core_dc, streams, stream_count))
 		return DC_OK;
@@ -862,18 +862,10 @@ bool dc_commit_streams(
 		const struct core_sink *sink = context->streams[i]->sink;
 
 		for (j = 0; j < context->stream_status[i].surface_count; j++) {
-			const struct dc_surface *dc_surface =
-					context->stream_status[i].surfaces[j];
-
-			for (k = 0; k < context->res_ctx.pool->pipe_count; k++) {
-				struct pipe_ctx *pipe = &context->res_ctx.pipe_ctx[k];
+			struct core_surface *surface =
+					DC_SURFACE_TO_CORE(context->stream_status[i].surfaces[j]);
 
-				if (dc_surface != &pipe->surface->public
-						|| !dc_surface->visible)
-					continue;
-
-				pipe->tg->funcs->set_blank(pipe->tg, false);
-			}
+			core_dc->hwss.apply_ctx_for_surface(core_dc, surface, context);
 		}
 
 		CONN_MSG_MODE(sink->link, "{%dx%d, %dx%d@%dKhz}",