drm/radeon: fix render backend setup for SI and CIK
drm/radeon: fix render backend setup for SI and CIK

From Marek Olsak
88aa6194df73e8dff9f2a1ee47d2775df3d99411 in ubuntu 3.8
9fadb352ed73edd7801a280b552d33a6040c8721 in mainline linux

orumin/openbsd-efivars,orumin/openbsd-efivars,orumin/openbsd-efivars,orumin/openbsd-efivars