[rtdbg] Update some comments on rtdbg.h.
* In your C/C++ file, enable/disable DEBUG_ENABLE macro, and then include this
* header file.
*
- * #undef DBG_SECTION_NAME // avoid the macro is already defined
- * #undef DBG_LEVEL
- * #undef DBG_COLOR
- * #undef DBG_ENABLE
- *
* #define DBG_SECTION_NAME "[ MOD]"
* #define DBG_ENABLE // enable debug macro
* #define DBG_LEVEL DBG_INFO
