dt-bindings: i2c: imx-lpi2c: Add properties and use unevaluatedProperties

dt-bindings: i2c: imx-lpi2c: Add properties and use unevaluatedProperties

Additional properties actually might appear (e.g. power-domains) so
describe all typical properties, reference generic i2c schema and use
unevaluatedProperties to fix dtbs_check warnings like:

  arch/arm64/boot/dts/freescale/imx8qxp-ai_ml.dt.yaml: i2c@5a800000:
    'assigned-clock-rates', 'assigned-clocks', 'clock-names', 'power-domains' do not match any of the regexes: 'pinctrl-[0-9]+'

  arch/arm64/boot/dts/freescale/imx8qxp-colibri-eval-v3.dt.yaml: i2c@5a800000:
    'touchscreen@2c' does not match any of the regexes: 'pinctrl-[0-9]+'

Signed-off-by: Krzysztof Kozlowski <krzk@kernel.org>
Reviewed-by: Rob Herring <robh@kernel.org>
Signed-off-by: Wolfram Sang <wsa@kernel.org>