ASoC: rt5670: add codec_reg node for debug

Add codec_reg device node to read/write registers

Signed-off-by: Bard Liao <bardliao@realtek.com>
ASoC: rt5670: correct default cache table

Some of the default values in reg_default are incorrect.

Signed-off-by: Bard Liao <bardliao@realtek.com>