healthd: logd: add timestamp to kernel logged battery messages

Aid monotonic to realtime logging synchronization correction in
the Android ecosystem by providing a periodic notification.  We
now have the following messages in the kernel logs:

- PM: suspend entry %Y-%m-%d %H:%M:%S.%09q UTC
- PM: suspend exit %Y-%m-%d %H:%M:%S.%09q UTC
- Suspended for %s.%03q seconds
- healthd: battery l=100 ... %Y-%m-%d %H:%M:%S.%09q UTC

Alter klogd to resynchronize on healthd messages as well.

NB: Time using strftime format, %q is a reference to fractional
second as introduced into log_time strptime method.

Bug: 21868540
Change-Id: I854afc0a07dff9c7f26d2b2f68990e52bf90e300