Implement notifications and gpe to support q35 ACPI PCI hot-plug.
Use 0xcc4 - 0xcd7 range for 'acpi-pci-hotplug' io ports.

Signed-off-by: Julia Suvorova <jusual@redhat.com>
Reviewed-by: Igor Mammedov <imammedo@redhat.com>
Reviewed-by: Marcel Apfelbaum <marcel.apfelbaum@gmail.com>
Message-Id: <20210713004205.775386-2-jusual@redhat.com>
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Reviewed-by: David Gibson <david@gibson.dropbear.id.au>