ide/pci: convert to qdev.

ide/pci: convert to qdev.

With this patch applied ide drives (when attached to a pci adapter) can
be created via -device, like this:

  -drive if=none,id=mydisk,file=/path/to/disk.img
  -device ide-drive,drive=mydisk,bus=ide.0,unit=0

Note that creating a master on ide1 doesn't work that way.  That is a
side effect of qemu creating a cdrom automagically even if you don't
ask for it.

Signed-off-by: Gerd Hoffmann <kraxel@redhat.com>
Signed-off-by: Blue Swirl <blauwirbel@gmail.com>