dt-bindings: iio: use lowercase hex in examples

Use lowercase hex in addresses in examples.

Signed-off-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>
Acked-by: Rob Herring <robh@kernel.org>
Link: https://lore.kernel.org/r/20230124081037.31013-4-krzysztof.kozlowski@linaro.org


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