This fixes when configuring with --without-default-devices:
$ qemu-system-mips64 -bios /dev/null -M malta
qemu-system-mips64: Unknown device 'piix4-usb-uhci' for bus 'PCI'
Fixes: 7c28b925b7e
Signed-off-by: Philippe Mathieu-Daudé <philmd@redhat.com>
Message-Id: <20190316200818.8265-2-philmd@redhat.com>