[workqueue] 添加了 workqueue 接口的注释

components/drivers/include/ipc/workqueue.h

@@ -67,6 +67,13 @@ rt_err_t rt_work_submit(struct rt_work *work, rt_tick_t time);
 rt_err_t rt_work_cancel(struct rt_work *work);
 #endif /* RT_USING_SYSTEM_WORKQUEUE */
 
+/**
+ * @brief Init a work item, and bind it with a callback function.
+ * 
+ * @param work          A pointer to work item object.
+ * @param work_func     A callback function will be called when this work item is being executed.
+ * @param work_data     A user data passed to the callback function as it's second parameter.
+ */
 rt_inline void rt_work_init(struct rt_work *work, void (*work_func)(struct rt_work *work, void *work_data),
                             void *work_data)
 {