ASoC: rsnd: makes rsnd_ssi_is_dma_mode() static

ssi.c only is using rsnd_ssi_is_dma_mode().
Let's move it as static function.

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