pc: add rombar to compat properties for pc-0.10 and pc-0.11

So '-M pc-0.10' and '-M pc-0.11' will use the fw_cfg rom load method
by default.
Signed-off-by: NGerd Hoffmann <kraxel@redhat.com>
Signed-off-by: NAnthony Liguori <aliguori@us.ibm.com>

hw/pc.c

@@ -1082,6 +1082,10 @@ static QEMUMachine pc_machine_v0_11 = {
             .driver   = "virtio-blk-pci",
             .property = "vectors",
             .value    = stringify(0),
+        },{
+            .driver   = "PCI",
+            .property = "rombar",
+            .value    = stringify(0),
         },
         { /* end of list */ }
     }
@@ -1109,6 +1113,10 @@ static QEMUMachine pc_machine_v0_10 = {
             .driver   = "virtio-blk-pci",
             .property = "vectors",
             .value    = stringify(0),
+        },{
+            .driver   = "PCI",
+            .property = "rombar",
+            .value    = stringify(0),
         },
         { /* end of list */ }
     },