vkernel - Unbreak 32-bit vkernel builds by fixing broken assertion

vkernel - Unbreak 32-bit vkernel builds by fixing broken assertion

* [ASSERT_]MP_LOCK_HELD() was not properly handling the new token
  t_count format.

* Rename and document the functions a bit better.  Currently our
  more expansive token test for (shared or exclusive) is not
  a perfect test because we don't want to eat cpu time iterating
  the thread's token array to check for shared tokens.  So we just
  check for a shared count.

  Works well for assertions, wouldn't work very well for conditional
  acquisition (of a shared token).

* Exclusive token tests are perfect.

Reported-by: tuxillo