stm32/system_stm32: Provide default value for HSI calibration.
If HSI is used the calibration value must be valid.  Fixes
@@ -416,6 +416,7 @@ void SystemClock_Config(void)
RCC_OscInitStruct.OscillatorType = MICROPY_HW_RCC_OSCILLATOR_TYPE;
RCC_OscInitStruct.HSEState = MICROPY_HW_RCC_HSE_STATE;
RCC_OscInitStruct.HSIState = MICROPY_HW_RCC_HSI_STATE;
+ RCC_OscInitStruct.HSICalibrationValue = RCC_HSICALIBRATION_DEFAULT;
#if defined(STM32H7)
RCC_OscInitStruct.CSIState = RCC_CSI_OFF;
#endif
