rtc: rv3029: let the core handle rtc range

Despite the comment, the RV3029 uses a 7bit BCD register for the year,
making 2079 the last supported year.

Link: https://lore.kernel.org/r/20191214221022.622482-14-alexandre.belloni@bootlin.com


Signed-off-by: Alexandre Belloni <alexandre.belloni@bootlin.com>