thermal: rcar_thermal: Always update thermal zone on interrupt

Since commit a1ade5653804b8eb ("thermal: rcar: check every
rcar_thermal_update_temp() return value") the temperature is always read
in rcar_thermal_get_current_temp() so comparing it before and after
enabling interrupts have little effect. Remove the check and always
update the thermal zone when we get an interrupt that the temperature
have changed.

Signed-off-by: Niklas Söderlund <niklas.soderlund+renesas@ragnatech.se>
Reviewed-by: Geert Uytterhoeven <geert+renesas@glider.be>
Signed-off-by: Daniel Lezcano <daniel.lezcano@linaro.org>
Link: https://lore.kernel.org/r/20200310170029.1648996-2-niklas.soderlund+renesas@ragnatech.se