regulator: Convert SY8106A binding to a schema

regulator: Convert SY8106A binding to a schema

The Silergy SY8106A is a regulator controlled through i2c supported by
Linux with a matching device tree binding.

Now that we have the DT validation in place, let's convert the device
tree bindings for that driver over to a YAML schema.

Cc: Icenowy Zheng <icenowy@aosc.io>
Cc: Liam Girdwood <lgirdwood@gmail.com>
Cc: Mark Brown <broonie@kernel.org>
Cc: Ondrej Jirman <megous@megous.com>
Reviewed-by: Rob Herring <robh@kernel.org>
Signed-off-by: Maxime Ripard <maxime@cerno.tech>
Link: https://lore.kernel.org/r/20210901091852.479202-34-maxime@cerno.tech
Signed-off-by: Mark Brown <broonie@kernel.org>