* Add SCSIBus.
 * Add SCSIDeviceInfo, move device callbacks here.
 * add qdev/scsi helper functions.
 * convert drivers.

Adding scsi disks via -device works now, i.e. you can do:

 -drive id=sda,if=none,...
 -device lsi
 -device scsi-disk,drive=sda

legacy command lines (-drive if=scsi,...) continue to work.
Signed-off-by: NGerd Hoffmann <kraxel@redhat.com>
Signed-off-by: NAnthony Liguori <aliguori@us.ibm.com>