dt-bindings: iio/adc: qcom,spmi-iadc: Fix 'reg' property in example

The QCom SPMI PMIC child nodes are defined to have a single address cell,
but the example has an erroneous size cell. Remove it.

Signed-off-by: Rob Herring <robh@kernel.org>
Link: https://lore.kernel.org/r/20220126231217.1633935-1-robh@kernel.org


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