This is a step towards getting the drivers ready for new config.
Clean up namespace, remove several instances of global arrays. Instead,
use a softc to carry state around. Where possible, pass a pointer to
the softc rather than a unit number.
Pointers to hardware and software constructs are now stored per port
in each instance of the softc (one softc per board) rather than indexed
by minor number.
deb00c27b3