atombios stuck executing D850 when trying to switch to 4k at 60Hz on Polaris10

[Clemens Eisserer]

Hi Alex,

> You need to use dc to support 4k at 60.  Remove amdgpu.dc=0 from the kernel command line in grub.

Thanks a lot!
Indeed, it worked immediatly after removing those left-overs from my
kaveri-based system.

Br, Clemens