hw/virtio/virtio-pci: Use pow2ceil() rather than hand-calculation

Use the utility function pow2ceil() for rounding up to the next
largest power of 2, rather than inline calculation.
Signed-off-by: NPeter Maydell <peter.maydell@linaro.org>
Reviewed-by: NMichael S. Tsirkin <mst@redhat.com>
Message-id: 1437741192-20955-3-git-send-email-peter.maydell@linaro.org

hw/virtio/virtio-pci.c

@@ -1505,9 +1505,7 @@ static void virtio_pci_device_plugged(DeviceState *d, Error **errp)
     if (legacy) {
         size = VIRTIO_PCI_REGION_SIZE(&proxy->pci_dev)
             + virtio_bus_get_vdev_config_len(bus);
-        if (size & (size - 1)) {
-            size = 1 << qemu_fls(size);
-        }
+        size = pow2ceil(size);
 
         memory_region_init_io(&proxy->bar, OBJECT(proxy),
                               &virtio_pci_config_ops,