wqueue: delete sem_wait to avoid race condition

when work_cancel was called, we need to check work.timer whether is active
by WDOG_ISACTIVE for work_queue with delay.

The wdog cb has not been executed when the flag:active is cleared
and if we check flag:active at this moment, WDOG_ISACTIVE will return false.
so the work_cancel will sem_wait until post a semaphore, but all free hpwork_thread
also wait this semphore and their priority are high than caller, this will be a race
condition causing thread/task of calling work_cancel block.

Change-Id: Id86289da60bf967d1062c1cdaaf6959b4f6dd054
Signed-off-by: Jiuzhu Dong <dongjiuzhu1@xiaomi.com>

sched/wqueue/kwork_cancel.c

@@ -87,17 +87,6 @@ static int work_qcancel(FAR struct kwork_wqueue_s *wqueue,
         }
       else
         {
-          /* The sem_wait() can't call from interrupt handlers, so worker
-           * thread will still be awakened even if the work cancel is
-           * called in interrupt handlers, but work thread can handle
-           * this case with work empty in the work queue.
-           */
-
-          if (up_interrupt_context() == false)
-            {
-              nxsem_wait(&wqueue->sem);
-            }
-
           sq_rem((FAR sq_entry_t *)work, &wqueue->q);
         }