RCC Exported Constants

Modules
	Oscillator Values adaptation
	Defines used to adapt values of different oscillators.
	Clear Flags Defines
	Flags defines which can be used with LL_RCC_WriteReg function.
	Get Flags Defines
	Flags defines which can be used with LL_RCC_ReadReg function.
	IT Defines
	IT defines which can be used with LL_RCC_ReadReg and LL_RCC_WriteReg functions.
	System clock switch
	System clock switch status
	AHB prescaler
	APB low-speed prescaler (APB1)
	APB high-speed prescaler (APB2)
	MCO1 SOURCE selection
	Peripheral clock frequency
	Peripheral USB clock source selection
	Peripheral ADC clock source selection
	Peripheral USB get clock source
	Peripheral ADC get clock source
	RTC clock source selection
	PLL Multiplicator factor
	PLL SOURCE
	PREDIV Division factor