Add iio-hwmon map for ls1028ardb

The ls1028ardb uses the TI ina220 power monitor. This device has an IIO and hwmon drivers, but can't be used with both at the same time. To enable us to utilise the iio framework, but also access power information via the hwmon framework, add an iio-hwmon map. This allows the IIO driver to be used for the ina220, with the iio-hwmon driver mapping the data from the IIO framework into hwmon.

Signed-off-by: Martyn Welch martyn.welch@collabora.com