On the official park maps, there is no campsite at this position (I have a bad photo).
I think it's not a good idea to make anyone beleeve that he can spend the night there. The ranger in Drekaskáli told us, that we are not allowed to spend the night there, only in case of emergency. We have to drive until Nyidalur.

The ranger in Drekaskáli (Askja) told us, so I think it's true.