drm/amd/display: Fix MST Multi-Stream Not Lighting Up on dcn35

dcn35 misses .enable_symclk_se hook that makes MST DSC
not functional when having multiple FE clk to be enabled.
Reviewed-by: Rodrigo Siqueira <rodrigo.siqueira@amd.com>
Acked-by: Roman Li <roman.li@amd.com>
Signed-off-by: Fangzhi Zuo <jerry.zuo@amd.com>
Tested-by: Daniel Wheeler <daniel.wheeler@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>

drivers/gpu/drm/amd/display/dc/hwss/dcn20/dcn20_hwseq.c

@@ -2746,6 +2746,8 @@ void dcn20_enable_stream(struct pipe_ctx *pipe_ctx)
 	struct dce_hwseq *hws = dc->hwseq;
 	unsigned int k1_div = PIXEL_RATE_DIV_NA;
 	unsigned int k2_div = PIXEL_RATE_DIV_NA;
+	struct link_encoder *link_enc = link_enc_cfg_get_link_enc(pipe_ctx->stream->link);
+	struct stream_encoder *stream_enc = pipe_ctx->stream_res.stream_enc;
 
 	if (dc->link_srv->dp_is_128b_132b_signal(pipe_ctx)) {
 		if (dc->hwseq->funcs.setup_hpo_hw_control)
@@ -2765,6 +2767,10 @@ void dcn20_enable_stream(struct pipe_ctx *pipe_ctx)
 		dto_params.timing = &pipe_ctx->stream->timing;
 		dto_params.ref_dtbclk_khz = dc->clk_mgr->funcs->get_dtb_ref_clk_frequency(dc->clk_mgr);
 		dccg->funcs->set_dtbclk_dto(dccg, &dto_params);
+	} else {
+		if (dccg->funcs->enable_symclk_se)
+			dccg->funcs->enable_symclk_se(dccg, stream_enc->stream_enc_inst,
+						      link_enc->transmitter - TRANSMITTER_UNIPHY_A);
 	}
 	if (hws->funcs.calculate_dccg_k1_k2_values && dc->res_pool->dccg->funcs->set_pixel_rate_div) {
 		hws->funcs.calculate_dccg_k1_k2_values(pipe_ctx, &k1_div, &k2_div);