kernel - ipv6 - Fix broken 'invalid mtu expiration time' message

* Fix broken 'invalid mtu expiration time' message on the console.

Reported-by: tuxillo
kernel - Change time_second to time_uptime for all expiration calculations

* Vet the entire kernel and change use cases for expiration calculations
  using time_second to use time_uptime instead.

* Protects these expiration calculations from step changes in the wall time,
  particularly needed for route table entries.

* Probably requires further variable type adjustments but the use of
  time_uptime instead if time_second is highly unlikely to ever overrun
  any demotions to int still present.
kernel - Change time_second to time_uptime for all expiration calculations (2)

* Fix userspace issues calculating rmx_expire for display due to
  time_second -> time_uptime change.

  The route, arp, ndp, and rarpd utilities are affected by this change.
kernel/ddb: Fix formatting when printing command tables.

FreeBSD's r163134:

Fixed formatting of printing of command tables.  With the default max
output width of 79, only 6 columns of width 12 each fit, but 7 columns
were printed.

The fix is to pass the width of the next output to db_end_line() and
not assume there that this width is always 1.

Related unfixed bugs:
- 1 character is wasted for a space after the last column
- suppression of trailing spaces used to limit the misformatting, but
  seems to have been lost
- in db_examine(), the width of the next output is not known and is
  still assumed to be 1.

Taken-from: FreeBSD