rtc: rx8025: round up to nearest minute for a minute accuracy alarm

The alarm for rx8025 only has a minute accuracy, so round up to nearest
minute when setting alarm.  Without doing this, rtctest blocks one day
after setting alarm to 5 seconds later.

pcf8563 and hym8563 also have similar handling.

Signed-off-by: Akinobu Mita <akinobu.mita@gmail.com>
Cc: Wolfgang Grandegger <wg@grandegger.com>
Cc: Alessandro Zummo <a.zummo@towertech.it>
Cc: Alexandre Belloni <alexandre.belloni@free-electrons.com>
Signed-off-by: Alexandre Belloni <alexandre.belloni@free-electrons.com>