FROMLIST: dt-bindings: iio: adc: Add binding for ADC on pms405 PMIC

PMS405 contains a variant of the spmi-adc-rev2 ADC. Create a new
compatible inorder to handle any differences.

am link: https://patchwork.kernel.org/patch/10725967/



Signed-off-by: Amit Kucheria <amit.kucheria@linaro.org>
Signed-off-by: Khasim Syed Mohammed <khasim.mohammed@linaro.org>