thermal/drivers/thermal-generic-adc: Add temperature sensor channel

To avoid duplicating sensor functionality and conversion tables, this
design allows converting an ADC IIO channel's output directly into a
temperature IIO channel. This is particularly useful for devices where
hwmon isn't suitable or where temperature data must be accessible through
IIO.

One such device is, for example, the MAX17040 fuel gauge.

Signed-off-by: Svyatoslav Ryhel <clamor95@gmail.com>
Reviewed-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Link: https://lore.kernel.org/r/20250903162749.109910-2-clamor95@gmail.com


Signed-off-by: Daniel Lezcano <daniel.lezcano@linaro.org>