rtc: ds1511: set alarm offset limit

The ds1511 can only support alarms up to a month in the future (which we
currently limit to 28 days).

Link: https://lore.kernel.org/r/[e-mail]
Signed-off-by: Alexandre Belloni <[e-mail]>

drivers/rtc/rtc-ds1511.c

···
 
 	ds1511->rtc->ops = &ds1511_rtc_ops;
 	ds1511->rtc->range_max = RTC_TIMESTAMP_END_2099;
+	ds1511->rtc->alarm_offset_max = 28 * 24 * 60 * 60 - 1;
 
 	/*
 	 * if the platform has an interrupt in mind for this device,