You'd need at least 3 mics to determine location on a single sound event, that's why they call it triangulation. If you're trying to determine just direction from a particular point then you could do it with 2 mics, but you'd never be able to determine the difference between sounds originating 180 degrees apart (you could figure out it was either 90 degrees from the direction you're facing or 270 degrees).
So, besides those limitations there's further limitations when trying to use the mics on a cell phone, even if it had three. The biggest is that the closer the mics are from each other, the lower the resolution is. Without doing the math, I'd guess that between the three mics being so close together and the sampling rate being what it is on the DACs in a phone you'd never be able to calculate any time differences between the mics to help you determine location. I could be wrong, but even if I am I don't think you could determine location with any sort of usable accuracy.