thermal/drivers/mediatek: Relocate driver to mediatek folder

Add MediaTek proprietary folder to upstream more thermal zone and cooler
drivers, relocate the original thermal controller driver to it, and rename it
as "auxadc_thermal.c" to show its purpose more clearly.

Signed-off-by: Balsam CHIHI <bchihi@baylibre.com>
Reviewed-by: AngeloGioacchino Del Regno <angelogioacchino.delregno@collabora.com>
Link: https://lore.kernel.org/r/20230209105628.50294-2-bchihi@baylibre.com
Signed-off-by: Daniel Lezcano <daniel.lezcano@linaro.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>