ASoC: rsnd: replace rsnd_dai_is_play() to rsnd_io_is_play()

Current rsnd driver can use rsnd_io_to_rdai()
we can get play/capture direction via io now.
Let's replace rsnd_dai_is_play() to rsnd_io_is_play()

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