qcacmn: Fix the memory leak for the wmi_rx_diag_work_queue

Add workqueue destroy in the wmi detach for the wmi_rx_diag_work_queue
to avoid the system memory leak.

Change-Id: Ic183ddaa2e53292a50e0b379877a92ddcaf45b02
CRs-Fixed: 3597405

wmi/src/wmi_unified.c

@@ -3440,7 +3440,10 @@ void wmi_unified_detach(struct wmi_unified *wmi_handle)
 						&soc->wmi_pdev[i]->event_queue);
 			}
 
-			qdf_flush_work(&soc->wmi_pdev[i]->rx_diag_event_work);
+			qdf_flush_workqueue(0,
+				soc->wmi_pdev[i]->wmi_rx_diag_work_queue);
+			qdf_destroy_workqueue(0,
+				soc->wmi_pdev[i]->wmi_rx_diag_work_queue);
 			buf = qdf_nbuf_queue_remove(
 					&soc->wmi_pdev[i]->diag_event_queue);
 			while (buf) {