Previously a debug kernel would panic, and a non-debug kernel would silently
allow integer overflows when setting the RTC. Now, settimeofday will
still set the in-memory clock, but it won't change the RTC.
- Tolerate leap seconds in vrtc.
- Don't do a BCD conversion in ddf_meta_create unless we really need to.
- Print RTC failures even if debug.bootverbose = 0
Reported by: Jan Schaumann <email@example.com>