ASoC: samsung-i2s: Use unevaluatedProperties

Additional properties actually might appear (e.g. power-domains) so use
unevaluatedProperties to fix dtbs_check warnings like:

  arch/arm64/boot/dts/exynos/exynos5433-tm2.dt.yaml: i2s@11440000:
    Additional properties are not allowed ('power-domains', '#address-cells', 'interrupts', '#size-cells' were unexpected)
Signed-off-by: Krzysztof Kozlowski <krzk@kernel.org>
Reviewed-by: Sylwester Nawrocki <s.nawrocki@samsung.com>
Link: https://lore.kernel.org/r/20200829142501.31478-6-krzk@kernel.orgSigned-off-by: Mark Brown <broonie@kernel.org>

Documentation/devicetree/bindings/sound/samsung-i2s.yaml

@@ -115,7 +115,7 @@ required:
   - clocks
   - clock-names
 
-additionalProperties: false
+unevaluatedProperties: false
 
 examples:
   - |