PowerPC: Transition back to CHRP script.

* After examining MacOS toolbox roms, I think i've got
  this nailed down. The MacOS Toolbox rom contains chrp
  code at the top and binary code at the bottom.
* The Raw format for the chrp seemed to cause issues with the
  OpenFirmware boot process on some systems.  NetBSD uses a '-'
  file type.
* The format of the chrp seems a lot more sensitive across machines
  than described. Ensure our returns and spaces are even.
* Booting with the 'c' key is still working on my older OpenFirmware
  machine with the chrp script. The bitmap logo is a half black, half
  white box.
* I removed the &device; alias for now for troubleshooing. It also may
  of been causing compatibility issues. More testing is needed.