EMX_NRX_RING
KASSERT(sc->rx_ring_cnt == EMX_NRX_RING,
for (i = 0; i < EMX_NRX_RING; ++i) {
for (i = 0; i < EMX_NRX_RING; ++i)
sc->rx_rmap = if_ringmap_alloc(dev, ring_cnt, EMX_NRX_RING);
struct emx_rxdata rx_data[EMX_NRX_RING];