A new board for "Poppy" was added yesterday to Coreboot Git. This Google Poppy board is indeed making use of an Intel Kabylake processor.
Details on Google Poppy are scarce from Google searches so there isn't much more beyond this commit. It's a Kabylake board, uses the FSP 2.0 package, etc. Though the board information marks it as the "Poppy Kabylake Reference Board", so there are chances it may just be a developer reference board for Intel Kabylake CPUs as opposed to a new Chromebook/Chromebox making it to market, but we should find out in 2017 when more Kabylake designs are hitting the market.