PCI host bridges need to set fw_name to be discoverable by bios for boot device selection. In particular, seabios expects root device to be called "/pci/@i0cf8", so let's set it up like that for Q35. Cc: qemu-stable@nongnu.org Signed-off-by: Michael S. Tsirkin <mst@redhat.com> Tested-by: Amos Kong <akong@redhat.com>