stm32/dma: Add DMAMUX configuration for H7 to fix dma_nohal_init.
stm32/dma: Add DMAMUX configuration for H7 to fix dma_nohal_init.

Fixes issue #5619.

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