regulator: dt-bindings: promote infineon buck converters to their own binding

These devices are regulators may need to make use of the common
regulator properties, but these are not permitted while only documented
in trivial-devices.yaml

Signed-off-by: Conor Dooley <conor.dooley@microchip.com>
Reviewed-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>
Reviewed-by: Mark Brown <broonie@kernel.org>
Link: https://lore.kernel.org/r/20240223-blabber-obnoxious-353e519541a6@spud


[groeck: Dropped empty line at end of patch]
Signed-off-by: Guenter Roeck <linux@roeck-us.net>