hw/s390x: Re-enable the pci-bridge device on s390x

Commit e779e5c ("hw/pci-bridge: Add a Kconfig switch for the
normal PCI bridge") added a config switch for the pci-bridge, so
that the device is not included in the s390x target anymore (since
the pci-bridge is not really useful on s390x).

However, it seems like libvirt is still adding pci-bridge devices
automatically to the guests' XML definitions (when adding a PCI
device to a non-zero PCI bus), so these guests are now broken due
to the missing pci-bridge in the QEMU binary.

To avoid disruption of the users, let's re-enable the pci-bridge
device on s390x for the time being.

Message-ID: <[email protected]>
Reviewed-by: Cédric Le Goater <[email protected]>
Reviewed-by: Boris Fiuczynski <[email protected]>
Reviewed-by: Philippe Mathieu-Daudé <[email protected]>
Signed-off-by: Thomas Huth <[email protected]>

hw/s390x/Kconfig

@@ -7,6 +7,7 @@ config S390_CCW_VIRTIO
     imply VFIO_AP
     imply VFIO_CCW
     imply WDT_DIAG288
+    imply PCI_BRIDGE
     imply PCIE_DEVICES
     imply IOMMUFD
     select PCI_EXPRESS