ASoC: rsnd: tidyup SSI init/start sequence

SSI want to have SSIWSR settings and SSICR settings without EN bit
when init, and SSICR EN bit only when start timing.
Otherwise, SSI output signal might be unstable.

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