Sadly, it is not. At least not under configuration DVB Inputs TV Adapters or Networks...
This is my docker-compose:
version: "2"
services:
  tvheadend:
    image: linuxserver/tvheadend
    container_name: tvheadend
    environment:
      - PUID=1000
      - PGID=1000
      - TZ=Europe/Berlin
    volumes:
      - /srv2/docker/tvheadend/config:/config
      - /srv2/docker/tvheadend/recordings:/recordings
    ports:
      - 9981:9981
      - 9982:9982
#    devices:
      #- /dev/dri:/dev/dri #optional
      #- /dev/drb:/dev/dvb #optional
    restart: unless-stopped