thermal: exynos: move trips setting to exynos_tmu_initialize()

* Add dummy exynos4210_tmu_set_trip_hyst() helper.

* Add ->tmu_set_trip_temp and ->tmu_set_trip_hyst methods to struct
  exynos_tmu_data and set them in exynos_map_dt_data().

* Move trips setting to exynos_tmu_initialize().

There should be no functional changes caused by this patch.

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