dt-bindings: iio: adc: npcm: Add npcm845 compatible string

Add a compatible string for Nuvoton BMC NPCM845 ADC.

Signed-off-by: Tomer Maimon <tmaimon77@gmail.com>
Reviewed-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>
Link: https://lore.kernel.org/r/20220713132640.215916-2-tmaimon77@gmail.com


Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>