The component numbering seems
to be retained with newer Pi versions.
Previously, mahjongg has confirmed
C106 as 220nF on a B+. I'd be confident that is still the case on a Pi3. It's likely the exact value won't matter anyway if it's a decoupling capacitor, and may even work without it.
Edit: it def is there on a Pi2, to the left of D3 on the PCB around the USB current limit circuitry.