ASoC: rt1015: remove bclk_ratio

bclk_ratio is unused.  Removes bclk_ratio and .set_bclk_ratio callback.

Removes snd_soc_dai_set_bclk_ratio() in a few machine drivers which are
obviously using rt1015.

Signed-off-by: Tzung-Bi Shih <tzungbi@google.com>
Link: https://lore.kernel.org/r/20201224101854.3024823-1-tzungbi@google.com
Signed-off-by: Mark Brown <broonie@kernel.org>