ASoC: rt5514: add rt5514 codec driver

This is the initial codec driver for rt5514. The codec includes a low power
DSP for voice wake up. The register address is incremental by 4 in the DSP
memory map. In order to recover the codec settings in the codec mode and
manipulate the DSP mode for voice wake up, we use the multi-level register
map. One is for ALSA API in codec mode that can be recovered by cache
before recording. Another is for DSP related settings that can be accessed
with 32bit address of the DSP in the application of voice wake up.

Signed-off-by: Oder Chiou <oder_chiou@realtek.com>
Signed-off-by: Mark Brown <broonie@kernel.org>