ASoC: sun8i-codec: Don't hardcode BCLK / LRCK ratio

BCLK / LRCK ratio should be sample size * channels, but it was
hardcoded to 32 (0x1 is 32 as per A33 and A64 datasheets).

Calculate it basing on sample size and number of channels.

Signed-off-by: Vasily Khoruzhick <anarsoul@gmail.com>
Acked-by: Maxime Ripard <maxime.ripard@bootlin.com>
Signed-off-by: Mark Brown <broonie@kernel.org>