I almost have no business answering this because I have not been Turkey. I used the bathroom, which was unisex and only for one person at a time, at a fancy looking restaurant in Italy, that had the hole in the floor style flush toilet, and the toilet in the men's room at one or more bus stations in Greece, had the hole-in-the-floor flush style toilet too.
This site gives you more about toilets in other countries:
In Turkey and Greece and certain other countries, the older hole-in-the-floor toilet use to be the only kind installed. Many have been replaced with "western" style toilets.
The closest thing to an answer you can probably get is: In many of the bathrooms you are likely to use, the toilets will be "western" style, the kind you can sit on. There is a non-zero chance that some bathrooms you will visit will have the older, hole-in-the-floor style toilet. Which ones you will encounter will be unknowable until you actually arrive at the bathroom. Be prepared for either one.