Remove the roll-your-own disklabel from CCD. Use the kernel disk manager

Remove the roll-your-own disklabel from CCD.  Use the kernel disk manager
for disklabel support instead.

Make CCD a real disk device rather then a fake one.  NOTE: All /dev/ccd*
devices have changed and must be remade

Introduce DSO_COMPATMBR.  This forces an MBR sector to be reserved in front
of a disklabel even when the target disk does not have slices.  It is used
by the CCD and VN devices to keep the disklabel aligned the same way it has
been historically.

Implement 64 bit block addressing for CCD.

Implement a new filesystem type "ccd", and require that the devices backing
the CCD use that filesystem type for safety.

Fix a bug in DIOCGPART where the partinfo->media_blocks was not being
set properly for partitions.