s390x: fix qom-ification fall-out

Tested-by: Andreas Faerber <afaerber@suse.de>
Signed-off-by: Anthony Liguori <aliguori@us.ibm.com>
diff --git a/vl.c b/vl.c
index 2d464cf..63dd725 100644
--- a/vl.c
+++ b/vl.c
@@ -1947,7 +1947,11 @@
     }
 
     bus_opts = qemu_opts_create(device, NULL, 0);
-    qemu_opt_set(bus_opts, "driver", "virtio-serial");
+    if (arch_type == QEMU_ARCH_S390X) {
+        qemu_opt_set(bus_opts, "driver", "virtio-serial-s390");
+    } else {
+        qemu_opt_set(bus_opts, "driver", "virtio-serial-pci");
+    } 
 
     dev_opts = qemu_opts_create(device, NULL, 0);
     qemu_opt_set(dev_opts, "driver", "virtconsole");