thermal: Make thermal_zone_device_is_enabled() available to core only

This function is not needed by drivers.

Signed-off-by: Andrzej Pietrasiewicz <andrzej.p@collabora.com>
Signed-off-by: Daniel Lezcano <daniel.lezcano@linaro.org>
Link: https://lore.kernel.org/r/20200703104354.19657-4-andrzej.p@collabora.com
3 files changed