Update the ta_rtc_{read,write}() functions in the todclock_attach_args
structure to take an argument attach time defined argument field as the
first argument.
- Implement new time-of-day device. This device provides the
inittodr() and resettodr() functions and is designed to be a child
device of an RTC device. This allows one of multiple RTC's attached
to be used to provide the basic time of day functions.