ASoC: rsnd: set SSIWSR setting on rsnd_ssi_config_init()

It will have TDM settings on SSIWSR. Actually, we would like to set
it on rsnd_ssi_config_init(), but we can't. Because SSI might be used
as clock master (It doesn't need to call rsnd_ssi_config_init() when
clock master mode).
This patch adds new ssi->wsr and set it on rsnd_ssi_start().

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