ASoC: rsnd: use dmaengine_prep_dma_cyclic() instead of original method

ASoC: rsnd: use dmaengine_prep_dma_cyclic() instead of original method

Current R-Car sound driver is using DMAEngine directly,
but, ASoC is requesting to use common DMA transfer method,
like snd_dmaengine_pcm_trigger() or dmaengine_pcm_ops.
It is difficult to switch at this point, since Renesas
driver is also supporting PIO transfer.
This patch uses dmaengine_prep_dma_cyclic() instead
of dmaengine_prep_slave_single().
It is used in requested method,
and is good first step to switch over.

Signed-off-by: Kuninori Morimoto <kuninori.morimoto.gx@renesas.com>
Signed-off-by: Mark Brown <broonie@linaro.org>
(cherry picked from commit ccd01559ead29b59918458e9b412ff18b88fc6cf)
Signed-off-by: Simon Horman <horms+renesas@verge.net.au>