It is not considered Turkey, by Turkey it is officially considered as Northern Cyprus, a separate country to Turkey, found in Asia. But you are correct, it isn't eligible for this promo, so you will have to change that.

Also important to note that Georgia and Azerbaijan are also considered as Europe for this promo, despite the fact that the cities TK flies to (Baku, Tbilisi, Batumi) are all technically in Asia. A tiny part of both countries are in Europe according to the standard '7 continents' definition that Turkey & TK uses, so that's why they are counted as Europe.