Cortex-M7 core's DTCM is available for other peripherals via a
dedicated address space. If transfers are done to or from the DTCM,
translate addresses to work on this shadow memory region instead, via
which the eDMA can access the DTCM.
This allows using the existing imxrt peripherals, which use DMA, to work
directly even if .data/.bss are located in DTCM.
Signed-off-by: Jukka Laitinen <jukka.laitinen@tii.ae>