fixed 2374c01b from https://gitee.com/hgbveiu743/kernel_liteos_m/pulls/1043

fix:pthread_cond_timedwait解锁后清理的问题
该函数解锁mutex 后先清理事件，导致等的事件丢失
Signed-off-by: Nyinjiaming <yinjiaming@huawei.com>
Change-Id: I36f8658b1b850734bc029b486fec103f6bd10588

kal/posix/src/pthread_cond.c

@@ -303,7 +303,6 @@ int pthread_cond_timedwait(pthread_cond_t *cond, pthread_mutex_t *mutex,
         PRINT_ERR("%s: %d failed\n", __FUNCTION__, __LINE__);
     }
 
-    (VOID)LOS_EventClear(&(cond->event), 0);
     ret = (INT32)LOS_EventRead(&(cond->event), 0x0f, LOS_WAITMODE_OR | LOS_WAITMODE_CLR, (UINT32)absTicks);
 
     if (pthread_mutex_lock(mutex) != 0) {