Enable DMA transfer mode for Intel Keem Bay ASoC platform driver.

The driver will search the device tree for DMA resources at boot
time to enable DMA transfer mode, and will proceed to use DMA
transfer if the resource is available, otherwise the default PIO
mode will be used.
Signed-off-by: Michael Sit Wei Hong <michael.wei.hong.sit@intel.com>
Reviewed-by: Pierre-Louis Bossart <pierre-louis.bossart@linux.intel.com>
Link: https://lore.kernel.org/r/20210108031248.20520-6-michael.wei.hong.sit@intel.comSigned-off-by: Mark Brown <broonie@kernel.org>