thermal/drivers/st: Switch from CONFIG_PM_SLEEP guards to pm_sleep_ptr()

thermal/drivers/st: Switch from CONFIG_PM_SLEEP guards to pm_sleep_ptr()

Letting the compiler remove these functions when the kernel is built
without CONFIG_PM_SLEEP support is simpler and less error prone than the
use of #ifdef based kernel configuration guards.

Remove those guards on every ST thermal related drivers.

Reviewed-by: Patrice Chotard <patrice.chotard@foss.st.com>
Signed-off-by: Raphael Gallais-Pou <rgallaispou@gmail.com>
Link: https://lore.kernel.org/r/20240716-thermal-v4-1-947b327e165c@gmail.com
Signed-off-by: Daniel Lezcano <daniel.lezcano@linaro.org>