The crank case vent runs from the driver's side valve cover into the plastic intake piece that attaches to the front of your turbo. This, in turn, then spreads the oil through the charge air pipes and cooler. That's where the oil comes from. Unless you're seeing tons of it (way more than a few teaspoons), that's pretty normal. The only thing would be, if the CCV has been re-routed - then you might have an issue.