Set DMA transfer mode for ColdFire.

After recent fixes to fsl edma engine, this mode can be used
also for ColdFire, and from some raw mtd r/w tests it definitely
improves the transfer rate, so keeping it selected.
Signed-off-by: Angelo Dureghello <angelo.dureghello@timesys.com>
Link: https://lore.kernel.org/r/20200816094635.1830006-1-angelo.dureghello@timesys.comSigned-off-by: Mark Brown <broonie@kernel.org>