publish_avail_idx does not read the used ring, no need to call bus_dmamap_sync for it.
publish_avail_idx does not read the used ring, no need to call
bus_dmamap_sync for it.

orumin/openbsd-efivars,orumin/openbsd-efivars,orumin/openbsd-efivars,orumin/openbsd-efivars