ASoC: dt-bindings: nau8821: Add DMIC slew rate.

Add input with DMIC slew rate controls.

Signed-off-by: Seven Lee <wtli@nuvoton.com>
Acked-by: Conor Dooley <conor.dooley@microchip.com>
Link: https://lore.kernel.org/r/20231107035230.1241683-2-wtli@nuvoton.com


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