hw/pci-bridge: Add acpi_uid property to TYPE_PXB_BUS

hw/pci-bridge: Add acpi_uid property to TYPE_PXB_BUS

Enable ACPI table creation for PCI Expander Bridges to be independent
of PCI internals.  Note that the UID is currently the PCI bus number.
This is motivated by the forthcoming ACPI Generic Port SRAT entries
which can be made completely independent of PCI internals.

Suggested-by: Igor Mammedov <imammedo@redhat.com>
Tested-by: "Huang, Ying" <ying.huang@intel.com>
Reviewed-by: Igor Mammedov <imammedo@redhat.com>
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Message-Id: <20240916171017.1841767-8-Jonathan.Cameron@huawei.com>
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>