I've added an installation from optical disk drive facility.
This enables FreeBSD to be installed from an optical disk, which
may be formatted in "super floppy" style or sliced into MSDOS-FS
and UFS partitions.
Note: ncr.c should be reviewed by Stefan Esser <se@freebsd.org>
and cd.c by Joerg Wunsch <joerg@freebsd.org> before bringing this
into 2.2.
Submitted-By: Shunsuke Akiyama <akiyama@kme.mei.co.jp>