It's a creative solution to foreseeable problem. But I can't help but doubt the feasibility of this idea. The the amount of fresh water during transit may decrease due to diffusion across the salty ocean. The cost of processing the ice for impurities and distribution may also be more expensive than sourcing saline water on nearer areas.
I think it is more likely feasible if the destination areas are closer to the source. Or, if there was an efficient way of processing and transporting the iceberg into smaller pieces to different parts of the world.