iio: hid-sensor-als: Use channel index to support more hub attributes

iio: hid-sensor-als: Use channel index to support more hub attributes

Sensor hub attributes can be extended to support more channels. Repeat
the reading for the two existing channels and store them separately. It
still operates in the same manner as before where there was just one
entry. So in order to support more sensor hub attributes for ALS use
channel index to get specific sensor hub attributes.

Signed-off-by: Basavaraj Natikar <Basavaraj.Natikar@amd.com>
Acked-by: Srinivas Pandruvada<srinivas.pandruvada@linux.intel.com>
Link: https://lore.kernel.org/r/20230919081054.2050714-2-Basavaraj.Natikar@amd.com
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>