Theres still more to do here, but at least the ifdef mess is gone. No
more checking for NULL before calling functions, that was playing with
fire. Oh yeah and lots more deletions :)

Clean up the debugger hooks, it was way too easy to screw up.
And we did. And Linus hit it.

- create CONFIG_DEBUGGER so we can enable kernel debugging options but not
  have any trace of debugger gunk.
- remove a bunch of xmon prototypes so no one gets the urge to call them
- Use die() instead of panic in a number of places, it gives us much better
  debug information.
- Get rid of the ifdef madness