wlan: Destroy 'ftmStopDoneEvent' in wda_stop().

As 'ftmStopDoneEvent' event is not destroyed, assert is observed
in following wda_start() while initializing this event.
Destroying ftmStopDoneEvent in wda_stop().

Change-Id: I7f0b8aa0383874699bacd86c7ee14078f3bfa79f
CRs-Fixed: 689141.
diff --git a/CORE/WDA/src/wlan_qct_wda.c b/CORE/WDA/src/wlan_qct_wda.c
index ab40a41..29885aa 100644
--- a/CORE/WDA/src/wlan_qct_wda.c
+++ b/CORE/WDA/src/wlan_qct_wda.c
@@ -2100,8 +2100,8 @@
          VOS_TRACE(VOS_MODULE_ID_VOSS, VOS_TRACE_LEVEL_ERROR,
                    "%s: FTM Stop Timepoout", __func__);
          VOS_ASSERT(0);
-         vos_event_reset(&pWDA->ftmStopDoneEvent);
       }
+      vos_event_destroy(&pWDA->ftmStopDoneEvent);
    }
    return status;
 }