If anything the earliest I would expect Macs to adopt AMD CPUs by next year.
Secondly. There is small Italian site, that has been pretty accurate when it goes to AMD information. They even got CPU core clocks right. And they say that AMD provided to Apple Raven Ridge APU engineering samples as early as December 2015, and that we have to expect AMD branded laptops in future.
http://www.bitsandchips.it/english/52-english-news/6183-apple-could-use-custom-x86-soc-made-by-amd
http://www.bitsandchips.it/english/52-english-news/7478-apu-zen-in-macbook-pro-between-2017-and-2018
However it will not happen earlier than Intel opening up Thunderbolt protocol. And the dates support this theory.
There is a possibility that it would be custom SoC, with HBM2 on package, 4C/8T and 16 CU design.
No where in those sources does it say AMD provided engineering samples to Apple.
The first source says "Apple is pondering about using custom x86 CPUs in its next iMacs and MacBooks". This does not mean those custom x86 CPUs have to be AMD branded. The site then offer its opinion that AMD could be a possible partner for this.
The second article by the same source simply says the same thing; "AMD could provide custom SoCs to Apple". Yeah, we all know they could. The question is are they going to? The answer is no as I have provided my sources already on why.