[Regression] "drm/amdgpu: enable gfxoff again on raven series (v2)"

[Kai-Heng Feng]

Hi,

After commit 005440066f92 ("drm/amdgpu: enable gfxoff again on raven series  
(v2)”), browsers on Raven Ridge systems cause serious corruption like this:
https://launchpadlibrarian.net/436319772/Screenshot%20from%202019-08-07%2004-20-34.png

Firmwares for Raven Ridge is up-to-date.

Kai-Heng