qcacmn: Fix duplicate process of link set event

Add flag in event response struct to indicate event processed
or not.
Use scheduler thread to process set link active event same as
other link switch and vdev event to avoid race condition.

Change-Id: I963f9106e296a59cff5078c85a4accf63c7026dc
CRs-Fixed: 3572868

target_if/mlo_mgr/src/target_if_mlo_mgr.c

@@ -416,7 +416,7 @@ target_if_mlo_register_event_handler(struct wlan_objmgr_psoc *psoc)
 			wmi_handle,
 			wmi_mlo_link_set_active_resp_eventid,
 			target_if_mlo_link_set_active_resp_handler,
-			WMI_RX_WORK_CTX);
+			WMI_RX_SERIALIZER_CTX);
 	if (QDF_IS_STATUS_ERROR(status)) {
 		target_if_err("Register mlo link set active resp cb errcode %d",
 			      status);