hw/acpi: Fix ordering of BDF in Generic Initiator PCI Device Handle.

hw/acpi: Fix ordering of BDF in Generic Initiator PCI Device Handle.

The ordering in ACPI specification [1] has bus number in the lowest byte.
As ACPI tables are little endian this is the reverse of the ordering
used by PCI_BUILD_BDF().  As a minimal fix split the QEMU BDF up
into bus and devfn and write them as single bytes in the correct
order.

[1] ACPI Spec 6.3, Table 5.80

Fixes: 0a5b5acdf2d8 ("hw/acpi: Implement the SRAT GI affinity structure")
Reviewed-by: Igor Mammedov <imammedo@redhat.com>
Tested-by: "Huang, Ying" <ying.huang@intel.com>
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Message-Id: <20240916171017.1841767-2-Jonathan.Cameron@huawei.com>
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>