ppc440_bamboo: Disable new virtio-serial features for 0.12 machine type

Disable the MULTIPORT feature and MSI vectors for the 0.12 machine
types; those features are added only for 0.13 onwards.

Signed-off-by: Amit Shah <amit.shah@redhat.com>
Signed-off-by: Aurelien Jarno <aurelien@aurel32.net>

hw/ppc440_bamboo.c

@@ -184,6 +184,18 @@ static QEMUMachine bamboo_machine_v0_12 = {
     .name = "bamboo-0.12",
     .desc = "bamboo",
     .init = bamboo_init,
+    .compat_props = (GlobalProperty[]) {
+        {
+            .driver   = "virtio-serial-pci",
+            .property = "max_nr_ports",
+            .value    = stringify(1),
+        },{
+            .driver   = "virtio-serial-pci",
+            .property = "vectors",
+            .value    = stringify(0),
+        },
+        { /* end of list */ }
+    },
 };
 
 static void bamboo_machine_init(void)