RELENG_7 DVD drive access in AHCI/SATA mode

[Scott I. Remick]

Might any of this also affect 6.2-STABLE at the moment? I have an all-
SATA Asus P5B Deluxe system, and haven't had much luck with my CDRW/DVD 
drive. If I have SATA set to "IDE" mode, data CDs seem to work but I get 
issues with audio CDs. If I set the SATA to "AHCI", my hard drives work 
but my CDRW/DVD drive isn't seen at all (and kicks an error on POST 
before FreeBSD even loads).

See kern/117215

I have everything on the Intel ICH8R controller... I'm thinking maybe 
moving the CD drive to the JMicron controller if support for that has 
improved.