tests: drivers: adc_dma: add nucleo_h743zi

Adds nucleo_h732zi ADC DMA unit tests with multiple channels.

The STM32 ADC DMA driver requires the buffers to be placed
in a non-cacheable memory region as defined by the DMA.
Therefore this adds configurability to the test to change
the region the buffer is placed in.

Signed-off-by: Hein Wessels <heinwessels93@gmail.com>