BURST_CAP
ret = lan78xx_write_reg(dev, BURST_CAP, dev->burst_cap);
ret = smsc75xx_write_reg(dev, BURST_CAP, buf);
ret = smsc75xx_read_reg(dev, BURST_CAP, &buf);
ret = smsc95xx_read_reg(dev, BURST_CAP, &read_buf);
ret = smsc95xx_write_reg(dev, BURST_CAP, burst_cap);