regulator: dt-bindings: samsung,s5m8767: Move fixed string BUCK9 to 'properties'

There's no need for a fixed string like 'BUCK9' to be under
'patternProperties', so move it under 'properties' instead.

Signed-off-by: Rob Herring <robh@kernel.org>
Link: https://lore.kernel.org/r/20211221120744.1118518-1-robh@kernel.org


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