iio: Add channel type light color temperature

In most cases, ambient color sensors also support light color
temperature, which is measured in kelvin. Thus, add channel type light
color temperature.

Signed-off-by: Basavaraj Natikar <Basavaraj.Natikar@amd.com>
Link: https://lore.kernel.org/r/20230919081054.2050714-3-Basavaraj.Natikar@amd.com


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