ASoC: rsnd: rename rsnd_runtime_is_ssi_xxx()

Current rsnd driver has rsnd_runtime_is_ssi_xxx() functions,
but it is not only related to SSI, thus, it is misunderstandable.
This patch renames it.

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