drivers: thermal: Update the hysteresis logic in governors

Thermal governors will throttle the cooling devices, when the temperature
exactly matches the hysteresis temperature. The threshold aggregation
logic will ignore the trip temperature, when it exactly matches the
current temperature. This will lead to a case where the governors will
throttle the cooling device, but the trip clear temperature wont be set
in the sensor. So the mitigation will never be cleared.

Change the governors to clear the mitigation, when the temperature
exactly matches the hysteresis threshold temperature.

Change-Id: Iff192b39009e47a0dfb6ca0217ef70ef51535ea5
Signed-off-by: Ram Chandrasekar <rkumbako@codeaurora.org>