RZ_A1H: cmsis nvic include fix

To get cmsis nvic definitions, this header file should be included
in cmsis.h file.

Fixes #5886

Author: 0xc0170

targets/TARGET_RENESAS/TARGET_RZ_A1XX/TARGET_RZ_A1H/device/cmsis.h

@@ -8,5 +8,6 @@
 #define MBED_CMSIS_H
 
 #include "MBRZA1H.h"
+#include "cmsis_nvic.h"
 
 #endif