Update MAKEDEV for acd* and cd* devices, the kernel now manages the

Update MAKEDEV for acd* and cd* devices, the kernel now manages the
disk layer for these devices.  Users have to regenerate their acd and cd
devices.

Create e.g. /dev/cd0 and /dev/acd0 as special raw access devices and
create e.g. /dev/cd0s0 and /dev/acd0s0 for label access.   This fixes
burncd on acd0 by allowing it to bypass the disk management layer entirely,
including bypassing the disk size checks in dscheck().

Implement the disk layer for NATA CD devices so it matches the ATA driver.

Tell CAM to create a compatibility 'a' slice for CDs (it wasn't before).