STM32 MDMAv1 driver.

Driver capability:

- The driver supports the STM32 complex MDMA controller found on H7
  sub-family.

The file registry must export:

STM32_MDMA_CHn_HANDLER      - Vector name for channel "n" (0..15).
STM32_MDMA_CHn_NUMBER       - Vector number for channel "n" (0..15).
