RT2560_RX_RING_COUNT
sc->rxq.cur = (sc->rxq.cur + 1) % RT2560_RX_RING_COUNT;
err = rt2560_alloc_rx_ring(sc, &sc->rxq, RT2560_RX_RING_COUNT);
tmp = RT2560_RX_RING_COUNT << 8 | RT2560_RX_DESC_SIZE;