How much are you looking to spend? Both the 17-55 f/2.8 and the 24-105 f/4 are great lenses but they're not cheap.
The Canon EF 24-105mm f/3.5-5.6 IS STM Lens is a relatively new offering from Canon is is considerably more affordable.
What phone are you looking at? The iPhone 6s models are all so similar I don't think it is going to make much of a difference which one you choose.
http://www.apple.com/iphone-6s/specs/