Convert autoconf hooks from old SCSI system to CAM.
busdma_machdep.c:
bus_dmamap_free() should expect the nobounce map, not a NULL one.
mountroot.c:
swapgeneric.c:
da and od changes.
symbols.raw:
Nuke the old disk stat symbols.
userconfig.c:
Disable the SCSI listing code until it can be converted to CAM.