Use the dedicated BCD macros from sys/time.h instead of handrolling our own for the m41t8x clocks.
Use the dedicated BCD macros from sys/time.h instead of handrolling
our own for the m41t8x clocks.

Tested by me and jasper@.
Okay jasper@, guenther@, deraadt@

orumin/openbsd-efivars,orumin/openbsd-efivars,orumin/openbsd-efivars,orumin/openbsd-efivars