M263: Include cmsis core_m23.h for macro __CORTEX_M in M261.h

Author: cyliangtw

targets/TARGET_NUVOTON/TARGET_M261/device/M261.h

@@ -190,7 +190,8 @@ typedef enum IRQn
 /*@}*/ /* end of group CMSIS */
 
 
-#include "core_armv8mbl.h"                  /* Processor and core peripherals */
+//#include "core_armv8mbl.h"                  /* Processor and core peripherals */
+#include "core_cm23.h"                      /* Processor and core peripherals */
 #include "system_M261.h"                   /* System Header */
 
 /**