ASoC: dt-bindings: nau8822: Add MCLK clock

Add nau8822 master clock input.

Signed-off-by: Francesco Dolcini <francesco.dolcini@toradex.com>
Reviewed-by: Rob Herring <robh@kernel.org>
Link: https://lore.kernel.org/r/20230719124752.248898-3-francesco@dolcini.it


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