ENETC_PSICFGR0_SET_TXBDR
val = ENETC_PSICFGR0_SET_TXBDR(num_tx_bdr);
val = ENETC_PSICFGR0_SET_TXBDR(ENETC_PF_NUM_RINGS);
val = ENETC_PSICFGR0_SET_TXBDR(num_rings);
val |= ENETC_PSICFGR0_SET_TXBDR(num_rings);