MID order.
- Export the shuffled MID order; other files now need it.
- Don't derive the GID from the unit number of the mcbus. A user could
render his kernel non-bootable by using a different unit number in the
kernel config file. We (and the hardware) only support one MCBUS, so
simply use instance 0. Note that this will need to be adjusted if there
are even any multiple-MCBUS systems.
thorpej