i386/acpi: show PCI Express bus on pxb-pcie expanders

i386/acpi: show PCI Express bus on pxb-pcie expanders

Show PCIe host bridge PNP id with PCI host bridge as a compatible id
when expanding a pcie bus.

Cc: qemu-stable@nongnu.org
Signed-off-by: Evgeny Yakovlev <wrfsh@yandex-team.ru>
Message-Id: <1563526469-15588-1-git-send-email-wrfsh@yandex-team.ru>
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
(cherry picked from commit ee4b0c8686f781987879508d7c6dd605b5435bac)
Signed-off-by: Michael Roth <mdroth@linux.vnet.ibm.com>