kernel - Uninline crit_exit()

kernel - Uninline crit_exit()

* Have crit_exit() call an actual procedure instead of inlining it.
  This doesn't seem to effect performance any and it reduces the
  size of the kernel noticeably.

  Modern cpus heavily optimize call/return paths these days and there
  might even be advantages to the smaller code and branch-cache footprint.
  The conditionals inside crit_exit() are nearly perfectly predicted
  now that there is no differentiation between the N->(N-1) and 1->0 case.