rtc: pcf8523: set range

Set the th RTC range, it is a classic BCD RTC, considering 00 as a leap
year. Let the core handle range checking.

Signed-off-by: Alexandre Belloni <alexandre.belloni@bootlin.com>
Link: https://lore.kernel.org/r/20201118002747.1346504-2-alexandre.belloni@bootlin.com