ASoC: rsnd: remove SH-DMA-BASE specific implementation

Renesas R-Car sound had SH-DMA-BASE specific implementation before,
but, now, it is no longer needed. Let's remove it.

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