We could specify 'model' for scsi controllers,
that means we could see more than one controllers
with same icon and blank details.
That will confuse users.
This patch will show details of scsi controller device.
And also we could modify scsi controller model
between 'default' and 'virtio-scsi'.
Signed-off-by: Chen Hanxiao <chenhanxiao@cn.fujitsu.com>