ASoC: rsnd: ssiu: clear SSI_MODE for non TDM Extended modes

register SSI_MODE is set when SSI works in TDM Extended,
but it isn't reset when SSI starts to work in other modes,
thus causes issues.

This patch clearss SSI_MODE register when SSI works in modes
other than TDM Extended.

Fixes: 186fadc1 ("ASoC: rsnd: add TDM Extend Mode support")
Signed-off-by: Jiada Wang <jiada_wang@mentor.com>
Acked-by: Kuninori Morimoto <kuninori.morimoto.gx@renesas.com>
Signed-off-by: Mark Brown <broonie@kernel.org>