ar40xx_hw_vtu_op
ret = ar40xx_hw_vtu_op(sc, op, val);
ret = ar40xx_hw_vtu_op(sc, AR40XX_VTU_FUNC1_OP_FLUSH, 0);
r = ar40xx_hw_vtu_op(sc, op, 0);
extern int ar40xx_hw_vtu_op(struct ar40xx_softc *sc, uint32_t op,