virtio_balloon: fix sparse warning

balloon uses virtio32_to_cpu instead of cpu_to_virtio32
to convert a native endian number to virtio.
No practical difference but makes sparse warn.
Fix it up.

Signed-off-by: Michael S. Tsirkin <[email protected]>
Reviewed-by: Cornelia Huck <[email protected]>
Acked-by: David Hildenbrand <[email protected]>
Reviewed-by: Cornelia Huck <[email protected]>
1 file changed