I've an AMD Ryzen 3 3200G with integrated Radeon Vega 8 graphics. I installed the latest AMD Ryzen drivers. I'm getting the same problem. Here's what DS_Dumpocl() gives:
Dunno what else to install, I googled but didn't find anything too clear.
EDIT: Here's the clinfo output
https://pastebin.com/qt38L9kn