thermal: core: Add upper and lower limits to power_actor_set_power

The upper and lower limits of thermal throttle state in the
DT do not apply to the Intelligent Power Allocation (IPA) governor.
Add the clamping for cooling device upper and lower limits in the
power_actor_set_power() used by IPA.

Signed-off-by: Michael Kao <michael.kao@mediatek.com>
Reviewed-by: Lukasz Luba <lukasz.luba@arm.com>
Tested-by: Lukasz Luba <lukasz.luba@arm.com>
Signed-off-by: Daniel Lezcano <daniel.lezcano@linaro.org>
Link: https://lore.kernel.org/r/20201007024332.30322-1-michael.kao@mediatek.com