acpi/pci: Move Generic Initiator object handling into acpi/pci.*

acpi/pci: Move Generic Initiator object handling into acpi/pci.*

Whilst ACPI SRAT Generic Initiator Afinity Structures are able to refer to
both PCI and ACPI Device Handles, the QEMU implementation only implements
the PCI Device Handle case.  For now move the code into the existing
hw/acpi/pci.c file and header.  If support for ACPI Device Handles is
added in the future, perhaps this will be moved again.

Also push the struct AcpiGenericInitiator down into the c file as not
used outside pci.c.

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: <20240916171017.1841767-7-Jonathan.Cameron@huawei.com>
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>