drm/amd/display: Call dsc related functions indirectly via dc interface

[Why&How]
Accessing dcn20_add_dsc_to_stream_resource directly
causes build failure for configuration which has
CONFIG_DRM_AMD_DC_DCN disabled. Fix this by
calling the corresponding function exposed via dc
resource functions.
Signed-off-by: Aurabindo Pillai <aurabindo.pillai@amd.com>
Reviewed-by: Nicholas Kazlauskas <Nicholas.Kazlauskas@amd.com>
Acked-by: Qingqing Zhuo <qingqing.zhuo@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>

drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_mst_types.c

@@ -806,7 +806,7 @@ bool compute_mst_dsc_configs_for_state(struct drm_atomic_state *state,
 		stream = dc_state->streams[i];
 
 		if (stream->timing.flags.DSC == 1)
-			dcn20_add_dsc_to_stream_resource(stream->ctx->dc, dc_state, stream);
+			dc_stream_add_dsc_to_resource(stream->ctx->dc, dc_state, stream);
 	}
 
 	return true;