MFC: r230633, r230634

MFC: r230633, r230634

Now that we have a working OF_printf() since r230631 and a OF_panic()
helper since r230632 (MFC'ed to stable/8 in r230885 and r230887
respectively), use these for output and panicing during the early
cycles and move cninit() until after the static per-CPU data has
been set up. This solves a couple of issue regarding the non-
availability of the static per-CPU data:
- panic() not working and only making things worse when called,
- having to supply a special DELAY() implementation to the low-level
  console drivers,
- curthread accesses of mutex(9) usage in low-level console drivers
  that aren't conditional due to compiler optimizations (basically,
  this is the problem described in r227537 but in this case for
  keyboards attached via uart(4)). [1]

PR:	164123 [1]

git-svn-id: svn://svn.freebsd.org/base/stable/8@230891 ccf9f872-aa2e-dd11-9fc8-001c23d0bc1f