thermal: exynos: check STATUS register in exynos_tmu_initialize()

STATUS register is present on all SoCs so move its checking into
exynos_tmu_initialize().

There should be no functional changes caused by this patch.

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>