Yes because it's technically in Southeast Asia. Plus, the Middle East, for the most part, speaks Arabic (expect for those french Lebanese) and they are Arab. Iran speaks Farsi and they are Persian.
Put it really doesn't matter how geographically accurate it is. If you've played the game you'd know that there are NO historically correct facts in the game. I think the game's designer just put it in "Persia" more for the games atmosphere and design than the geographical and historical landscape.
So just like the game, the movie could make a mockery of Persian ancestry, but as long as it's good, it'll make a 100 mil box office.