thermal: exynos: remove parsing of samsung, tmu_[first, second]_point_trim properties

All SoCs use the same values (25, 85) for trim points (except
Exynos5440 which currently specifices value 70 for the second trim
point -> it seems to be a mistake because documentation uses value
85 and two points based trimming has never been used by the driver
for this SoC anyway) so just make it explicit and remove parsing of
samsung,tmu_[first,second]_point_trim properties.

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>