stm32/powerctrl: Define RCC_SR_SFTRSTF flag for H747.
stm32/powerctrl: Define RCC_SR_SFTRSTF flag for H747.

adafruit/circuitpython,adafruit/circuitpython,bvernoux/micropython,bvernoux/micropython,bvernoux/micropython,adafruit/circuitpython,bvernoux/micropython,henriknelson/micropython,bvernoux/micropython,henriknelson/micropython,henriknelson/micropython,adafruit/circuitpython,henriknelson/micropython,adafruit/circuitpython,adafruit/circuitpython,henriknelson/micropython