ASoC: rsnd: remove un-needed parameter from rsnd_dma_init()

It can get DMA direction via rsnd_dai_stream.
Remove un-needed is_play from rsnd_dma_init().

Signed-off-by: Kuninori Morimoto <kuninori.morimoto.gx@renesas.com>
Signed-off-by: Mark Brown <broonie@kernel.org>