Add support of generic IIO channel binding: ./devicetree/bindings/iio/adc/adc.yaml Keep support of st,adc-channels for backward compatibility. Signed-off-by: Olivier Moysan <olivier.moysan@foss.st.com> Change-Id: Ifb433baf31af3661271d98b7c155958aa5f7afdb Reviewed-on: https://gerrit.st.com/c/mpu/oe/st/u-boot/+/238839 Reviewed-by: CITOOLS <MDG-smet-aci-reviews@list.st.com> Reviewed-by: Fabrice GASNIER <fabrice.gasnier@foss.st.com> Reviewed-by: Patrick DELAUNAY <patrick.delaunay@foss.st.com>