ASoC: sun4i-i2s: bclk and lrclk polarity tidyup

On newer SoCs the bit fields for the blck and lrclk polarity are in
a different locations. Use regmap fields to set the polarity bits
as intended.

Signed-off-by: Marcus Cooper <codekipper@gmail.com>
Reviewed-by: Chen-Yu Tsai <wens@csie.org>
Signed-off-by: Mark Brown <broonie@kernel.org>