rtc: m41t80: set range

This is a standard BCD RTC that will fail in 2100. The century bits don't
help because 2100 will be considered a leap year while it is not.

Link: https://lore.kernel.org/r/20191003213544.5359-1-alexandre.belloni@bootlin.com


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