thermal: exynos: clear IRQs later in exynos4412_tmu_initialize()

Clear IRQs after enabling thermal tripping (it should make no
difference in driver operation). This prepares the driver code
to moving IRQs clearing call from ->tmu_initialize method to
exynos_tmu_initialize().

Signed-off-by: Bartlomiej Zolnierkiewicz <b.zolnierkie@samsung.com>
Reviewed-by: Daniel Lezcano <daniel.lezcano@linaro.org>
Signed-off-by: Eduardo Valentin <edubezval@gmail.com>