AP_InternalError: added iomcu_reset critical error

libraries/AP_InternalError/AP_InternalError.h

@@ -45,6 +45,7 @@ public:
         logger_dequeue_failure      = (1U <<  9),
         constraining_nan            = (1U << 10),
         watchdog_reset              = (1U << 11),
+        iomcu_reset                 = (1U << 12),
     };
 
     void error(const AP_InternalError::error_t error);