hw/isa/piix3: Create USB controller in host device
The USB controller is an integral part of PIIX3 (function 2). So create
it as part of the south bridge.
Note that the USB function is optional in QEMU. This is why it gets
object_initialize_child()'ed in realize rather than in instance_init.
Signed-off-by: Bernhard Beschow <shentey@gmail.com>
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
Message-Id: <
20231007123843.127151-13-shentey@gmail.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>