I am 6 ft tall, coming from a 5'11" mom and a 6'2" dad. My sister (no CF) is 5'9". So no, I don't think CF stunted my growth. I did grow later than most kids though - probably b/c I didn't go through puberty until almost 16, as with a lot of CF women. But I grew just fine once I got started.
I will say this: I have a CF friend who was MUCH better about taking enzymes than I ever was growing up, and she did have stunted growth, definitely from the CF. She has more digestive issues and developed CFRD early, etc -- although I have always been more underweight than she was/is. But like the respiratory side, compliance is just one piece of the puzzle with the digestive issues. Some CFers who are very compliant will still face a lot of troubles here, others will be able to get away with more.