ASoC: sun4i-i2s: Add regfields for word size select and sample resolution

On newer SoCs the location of the slot width select and sample
resolution are different and also there is a bigger range of
support.

For the current supported rates then an offset is required.

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