drm/amdgpu/display/dc: do blocked MST topology discovery at resume from S3/S4

Why:
When resume from sleep or hiberation, blocked MST Topology discovery might
need to be used.

How:
Added "DETECT_REASON_RESUMEFROMS3S4" to enum dc_detect_reason; use it to
require blocked MST Topology discovery.
Reviewed-by: NWenjing Liu <Wenjing.Liu@amd.com>
Acked-by: NJasdeep Dhillon <jdhillon@amd.com>
Signed-off-by: NBing Guo <Bing.Guo@amd.com>
Tested-by: NDaniel Wheeler <daniel.wheeler@amd.com>
Signed-off-by: NAlex Deucher <alexander.deucher@amd.com>

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

@@ -831,7 +831,7 @@ static bool discover_dp_mst_topology(struct dc_link *link, enum dc_detect_reason
 	link->type = dc_connection_mst_branch;
 	dm_helpers_dp_update_branch_info(link->ctx, link);
 	if (dm_helpers_dp_mst_start_top_mgr(link->ctx,
-			link, reason == DETECT_REASON_BOOT)) {
+			link, (reason == DETECT_REASON_BOOT || reason == DETECT_REASON_RESUMEFROMS3S4))) {
 		link_disconnect_sink(link);
 	} else {
 		link->type = dc_connection_sst_branch;

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

@@ -312,6 +312,7 @@ void dc_link_blank_dp_stream(struct dc_link *link, bool hw_init);
  */
 enum dc_detect_reason {
 	DETECT_REASON_BOOT,
+	DETECT_REASON_RESUMEFROMS3S4,
 	DETECT_REASON_HPD,
 	DETECT_REASON_HPDRX,
 	DETECT_REASON_FALLBACK,