That click is not going to be anything to do with the chipset that the phone is using, that click is a cap discharge after the headphone amp is turned of internally.
I think people are blowing up this 6S sound quality issue to be more than something it is.
1. Ok you might be ablle to hear some whistling or buzzing when asking the processor to do something, but if the phone is otherwise dead silent then it's not going to impact on your listening.
2. A click or pop a second or so after stopping the music is not going to impact on your listening.
So far, in this thread, I've seen nothing that would prevent me from buying a 6S, even if all I was going to do with it is listen to music
I think people are concerned that if the phone is making noises under any conditions, it may well be making them while music is playing and therefore downgrading SQ. I haven't heard any evidence of this but as I have said, my hearing is not the best.