ARM: dts: stm32: add ADC support on stm32h743

Add support for ADC (Analog to Digital Converter) to STM32H743.
It has 3 ADCs, distributed over two ADC blocks:
- ADC1 and ADC2 @0x40022000
- ADC3 @0x58026000 (instantiated separately)

Signed-off-by: Fabrice Gasnier <fabrice.gasnier@st.com>
Signed-off-by: Alexandre Torgue <alexandre.torgue@st.com>