ASoC: dt-bindings: dialog,da7219: convert to dtschema

- Convert Dialog DA7219 bindings to DT schema format.
- Remove unused `dlg,ldo-lvl` property.

Signed-off-by: David Rau <David.Rau.opensource@dm.renesas.com>
Reviewed-by: Conor Dooley <conor.dooley@microchip.com>
Link: https://lore.kernel.org/r/20230523161821.4260-2-David.Rau.opensource@dm.renesas.com


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