ASoC: nau8821: add new widget to control system clock

Add new widget to control system clock for power saving.

Signed-off-by: Wallace Lin <savagecin0@gmail.com>
Signed-off-by: Wallace Lin <sjlin0@nuvoton.com>
Link: https://lore.kernel.org/r/20220719084047.11572-1-savagecin@gmail.com


Signed-off-by: Mark Brown <broonie@kernel.org>