ASoC: dt-bindings: maxim,max98357a: Convert to DT schema

Convert the Maxim Integrated MAX98357A/MAX98360A amplifier bindings to
DT schema.  Add missing properties ('#sound-dai-cells' and
'sound-name-prefix' from common DAI properties).

Signed-off-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>
Link: https://lore.kernel.org/r/20221203160442.69594-3-krzysztof.kozlowski@linaro.org
Signed-off-by: Mark Brown <broonie@kernel.org>