drm/dp_mst: Set CLEAR_PAYLOAD_ID_TABLE as broadcast

[Why & How]
According to DP spec, CLEAR_PAYLOAD_ID_TABLE is a path broadcast request
message and current implementation is incorrect. Fix it.
Signed-off-by: Wayne Lin <Wayne.Lin@amd.com>
Cc: stable@vger.kernel.org
Reviewed-by: Lyude Paul <lyude@redhat.com>
Signed-off-by: Lyude Paul <lyude@redhat.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20210224101521.6713-3-Wayne.Lin@amd.com

drivers/gpu/drm/drm_dp_mst_topology.c

@@ -1154,6 +1154,7 @@ static void build_clear_payload_id_table(struct drm_dp_sideband_msg_tx *msg)
 
 	req.req_type = DP_CLEAR_PAYLOAD_ID_TABLE;
 	drm_dp_encode_sideband_req(&req, msg);
+	msg->path_msg = true;
 }
 
 static int build_enum_path_resources(struct drm_dp_sideband_msg_tx *msg,
@@ -2822,7 +2823,8 @@ static int set_hdr_from_dst_qlock(struct drm_dp_sideband_msg_hdr *hdr,
 
 	req_type = txmsg->msg[0] & 0x7f;
 	if (req_type == DP_CONNECTION_STATUS_NOTIFY ||
-		req_type == DP_RESOURCE_STATUS_NOTIFY)
+		req_type == DP_RESOURCE_STATUS_NOTIFY ||
+		req_type == DP_CLEAR_PAYLOAD_ID_TABLE)
 		hdr->broadcast = 1;
 	else
 		hdr->broadcast = 0;