移除已经废弃的CPU使用率相关的字段和初始化代码

include/rtdef.h

@@ -895,10 +895,6 @@ struct rt_thread
     void                        *si_list;               /**< the signal infor list */
 #endif /* RT_USING_SIGNALS */
 
-#ifdef RT_USING_CPU_USAGE
-    rt_uint64_t                 duration_tick;          /**< cpu usage tick */
-#endif /* RT_USING_CPU_USAGE */
-
 #ifdef RT_USING_PTHREADS
     void                        *pthread_data;          /**< the handle of pthread data, adapt 32/64bit */
 #endif /* RT_USING_PTHREADS */

src/thread.c

@@ -277,10 +277,6 @@ static rt_err_t _thread_init(struct rt_thread *thread,
     thread->system_time = 0;
 #endif
 
-#ifdef RT_USING_CPU_USAGE
-    thread->duration_tick = 0;
-#endif /* RT_USING_CPU_USAGE */
-
 #ifdef RT_USING_PTHREADS
     thread->pthread_data = RT_NULL;
 #endif /* RT_USING_PTHREADS */