All you need is opening a terminal and issuing:
sudo touch /etc/modprobe.d/50-blacklist-rndis.conf
or, if you want to be more selective,
sudo cp /usr/lib/modprobe.d/50-blacklist-rndis.conf /etc/modprobe.d/50-blacklist-rndis.conf
then comment out the last line in /etc/modprobe.d/50-blacklist-rndis.conf so that it reads:
blacklist rndis_wlan
blacklist usb_f_rndis
# blacklist rndis_host
If you just need it once in a while, you may also issue:
sudo modprobe rndis_host
only when you need tethering.