Continue phasing out aic3x_read_reg_cache, aic3x_write_reg_cache, aic3x_read
and aic3x_write calls.

This patch takes the soc-cache in use and removes aic3x_read_reg_cache and
aic3x_write.
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>