ASoC: tlv320aic3x: Complete the soc-cache conversion

Complete the phasing out of aic3x_read_reg_cache, aic3x_write_reg_cache,
aic3x_read and aic3x_write calls.

This patch uses in aic3x_read the codec->hw_read that points to a function
implemented by soc-cache. Only use for aic3x_read is if wanting to read
volatile bits from those registers that has both read-only and read/write
bits. All other cases should use snd_soc_read.

Signed-off-by: Jarkko Nikula <jhnikula@gmail.com>
Acked-by: Mark Brown <broonie@opensource.wolfsonmicro.com>
Signed-off-by: Liam Girdwood <lrg@slimlogic.co.uk>