pc: Add back PCI.rombar compat property

This was erroneously dropped in d6c73008
(pc: reduce duplication in compat machine types).
Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>
Signed-off-by: NAndreas Färber <afaerber@suse.de>
Acked-by: NMichael S. Tsirkin <mst@redhat.com>

hw/pc_piix.c

@@ -522,6 +522,10 @@ static QEMUMachine pc_machine_v0_12 = {
             .driver   = "virtio-blk-pci",\
             .property = "vectors",\
             .value    = stringify(0),\
+        },{\
+            .driver   = "PCI",\
+            .property = "rombar",\
+            .value    = stringify(0),\
         }
 
 static QEMUMachine pc_machine_v0_11 = {