ASoC: xlnx: add pcm formatter platform driver

The audio formatter PL IP supports DMA of two streams -
mm2s and s2mm for playback and capture respectively. Apart from
DMA, IP also does conversions like PCM to AES and viceversa.
This patch adds DMA component driver for the IP.

Signed-off-by: Maruthi Srinivas Bayyavarapu <maruthi.srinivas.bayyavarapu@xilinx.com>
Signed-off-by: Mark Brown <broonie@kernel.org>