rtc: rx8010: use range checking provided by core RTC code

We don't need to check the time range manually in set_time(), we can
use range_min and range_max exposed by struct rtc_device.

Signed-off-by: Bartosz Golaszewski <bgolaszewski@baylibre.com>
Signed-off-by: Alexandre Belloni <alexandre.belloni@bootlin.com>
Link: https://lore.kernel.org/r/20200914154601.32245-15-brgl@bgdev.pl