arm64: dts: mediatek: cherry: Add platform thermal configuration

This platform has three auxiliary NTC thermistors, connected to the
SoC's ADC pins. Enable the auxadc in order to be able to read the
ADC values, add a generic-adc-thermal LUT for each and finally assign
them to the SoC's thermal zones.

Tested-by: Chen-Yu Tsai <wenst@chromium.org>
Reviewed-by: Chen-Yu Tsai <wenst@chromium.org>
Reviewed-by: Alexandre Mergnat <amergnat@baylibre.com>
Signed-off-by: AngeloGioacchino Del Regno <angelogioacchino.delregno@collabora.com>
Link: https://lore.kernel.org/r/20230424112523.1436926-2-angelogioacchino.delregno@collabora.com