atapicd regression

src/sys/dev/ata/atapi-cd.c r1.194 really broke how cd's work on my laptop, a few 
things happen when I use this revision:

  * when inserting a CD, mount /cdrom returns an immediate I/O error, while 
    before it would wait for the cd to be read then mount it.
  * the eject cli utilitiy returns 'device busy' in every situation, wether the 
    cd is mounted or not.
  * when i finish reading a cd and umount it, it's impossibly to manually use 
    the (physical) eject button on my cdrom until the cd has completely spun 
    down.  before the eject button would stop the reading immediatly and eject.

I can confirm that going to r1.193 restores previous functionality.

This is a laptop, a Dell Inspiron 8600 from 2003-11-16, Intel ICH4 chipset 
(82801DB).  I've also confirmed with a couple of others that they have hit this 
problem as well, all laptop users.  The only other person that hasn't had this 
problem is a desktop user.


Amar.