ASoC: dt-bindings: rockchip: i2s-tdm: Add RK3588 compatible

This adds the compatible string for the RK3588 SoC.

Signed-off-by: Nicolas Frattaroli <frattaroli.nicolas@gmail.com>
Acked-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>
Link: https://lore.kernel.org/r/20221025124132.399729-4-frattaroli.nicolas@gmail.com


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