thermal: exynos: remove threshold_code checking from exynos4210_tmu_initialize()

On Exynos4210 one-point trimming is always used and data->temp_error1
is equal to 75. Therefore temp_to_code() will never return negative
value for the reference temperature conversion.

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>