Adding support for Analog Devices MAX313XX series RTCs. This is ported from the Linux driver and adapted for use in u-boot. Notable differences are - handling of tm_year and tm_mon differ - clock source support is omitted - hwmon support for the MAX31328 and MAX31343 is omitted - rtc_ops->reset is added Signed-off-by: Chris Packham <judge.packham@gmail.com> Reviewed-by: Simon Glass <sjg@chromium.org>