ASoC: dt-bindings: Add schema for "awinic,aw88395"

Add a DT schema for describing Awinic AW88395 audio amplifiers. They are
controlled using I2C.

Signed-off-by: Weidong Wang <wangweidong.a@awinic.com>
Reviewed-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>
Link: https://lore.kernel.org/r/20230113055301.189541-6-wangweidong.a@awinic.com


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