hw/i386/acpi-build: Use AcpiPciHpState::root in acpi_set_pci_info

hw/i386/acpi-build: Use AcpiPciHpState::root in acpi_set_pci_info

pcihp acpi_set_pci_info() generic code currently uses
acpi_get_i386_pci_host() to retrieve the pci host bridge.

To make it work also on ARM we get rid of that call and
directly use AcpiPciHpState::root.

Signed-off-by: Eric Auger <eric.auger@redhat.com>
Suggested-by: Igor Mammedov <imammedo@redhat.com>
Reviewed-by: Igor Mammedov <imammedo@redhat.com>
Reviewed-by: Jonathan Cameron <jonathan.cameron@huawei.com>
Message-Id: <20250714080639.2525563-16-eric.auger@redhat.com>
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>