With code landing over the past week, initial support for Stoney Ridge is in place and passed review.
Stoney Ridge makes use of Excavator CPU cores and GCN GPU cores. Stoney is the successor to Carrizo and is considered AMD's 7th Generation APU.
While the Stoney support is in place in Coreboot, it doesn't appear that any Stoney motherboards/laptops are yet supported by Coreboot. This initial Stoney support appears to have been done in large part by Marc Jones, who does contract work around firmware development, Chrome OS firmware development, etc.
It's a pity the AMD Coreboot community isn't more vibrant compared to some years back when they kept their AGESA opened up and were more punctual in ensuring Coreboot support for their products.