drm/amd/display: extract update stream allocation to link_hwss

[Why & How]
Extract update stream allocation table into link hwss as part of the
link hwss refactor work.
Tested-by: Daniel Wheeler <daniel.wheeler@amd.com>
Reviewed-by: George Shen <George.Shen@amd.com>
Acked-by: Alan Liu <HaoPing.Liu@amd.com>
Signed-off-by: Wenjing Liu <wenjing.liu@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>

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

@@ -3871,7 +3871,6 @@ enum dc_status dc_link_increase_mst_payload(struct pipe_ctx *pipe_ctx, uint32_t
 	struct fixed31_32 avg_time_slots_per_mtp;
 	struct fixed31_32 pbn;
 	struct fixed31_32 pbn_per_slot;
-	struct link_encoder *link_encoder = link->link_enc;
 	struct dp_mst_stream_allocation_table proposed_table = {0};
 	uint8_t i;
 	enum act_return_status ret;
@@ -3915,8 +3914,13 @@ enum dc_status dc_link_increase_mst_payload(struct pipe_ctx *pipe_ctx, uint32_t
 	ASSERT(proposed_table.stream_count > 0);
 
 	/* update mst stream allocation table hardware state */
-	link_encoder->funcs->update_mst_stream_allocation_table(
-			link_encoder,
+	if (link_hwss->ext.update_stream_allocation_table == NULL ||
+			dp_get_link_encoding_format(&link->cur_link_settings) == DP_UNKNOWN_ENCODING) {
+		DC_LOG_ERROR("Failure: unknown encoding format\n");
+		return DC_ERROR_UNEXPECTED;
+	}
+
+	link_hwss->ext.update_stream_allocation_table(link, &pipe_ctx->link_res,
 			&link->mst_stream_alloc_table);
 
 	/* poll for immediate branch device ACT handled */