Fantarget was dropped in latest firmware and cgm driver, since there is a temptarget. Because of compatibility with older firmware, the fantarget is set by cgm driver to 255.
If you want to monitor an actual fan speed (or current pwm level, since fan rpm measurement is not implemented in firmware yet), you have to take a look at klninfo->status[dev].kline.ws.fanspeed variable.
You can review K16 firmware at github.com/zipiju/k16-firmware.
Thanks! I'll make that change in my branch.