Upvote:3
According to TLSContact (the company handling Swiss visas in Turkey):
The average application process time is 6 to 8 working days, but it can take much longer under certain circumstances (e.g. missing documents, work visa, etc.). The Consulate General advises you to submit your application at least 15 calendar days before the scheduled departure.
So presuming you want to be on the safe side, I'd plan at least 10 days in Istanbul. Note that you can also have someone else pick up your passport or have the consulate send your documents by UPS, although I'm not sure how reliable UPS is for deliveries to Iraq.