wpi_alloc_tx_ring
static int wpi_alloc_tx_ring(struct wpi_softc *, struct wpi_tx_ring *,
error = wpi_alloc_tx_ring(sc, &sc->txq[ac], WPI_TX_RING_COUNT,
error = wpi_alloc_tx_ring(sc, &sc->cmdq, WPI_CMD_RING_COUNT, 4);