!688 fix: 修改内核子系统markdown文件目录错误问题

Merge pull request !688 from Kiita/220510_md

arch_spec.md

@@ -94,6 +94,5 @@
     ├── los_hook.h
     ├── los_list.h                                             --- Doubly linked list
     └── los_reg.h                                              --- Register macros
-    └── src
 ```
 

arch_spec_zh.md

@@ -93,6 +93,5 @@
     ├── los_hook.h
     ├── los_list.h                                              --- 双向链表
     └── los_reg.h                                               --- 寄存器读写宏定义
-    └── src
 ```