thermal: exynos: add exynos*_tmu_set_[trip,hyst]() helpers

Add exynos*_tmu_set_[trip,hyst]() helpers and convert
all ->tmu_initialize implementations accordingly.

Signed-off-by: Bartlomiej Zolnierkiewicz <b.zolnierkie@samsung.com>
Signed-off-by: Eduardo Valentin <edubezval@gmail.com>