ASoC: dai_dma: remove slave_id field

This field is no longer set from any driver now, so remove the
last references as well.

Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Acked-by: Mark Brown <broonie@kernel.org>
Link: https://lore.kernel.org/r/20211122222203.4103644-3-arnd@kernel.org


Signed-off-by: Vinod Koul <vkoul@kernel.org>