drm/radeon: do not try to uselessly update virtual memory pagetable
drm/radeon: do not try to uselessly update virtual memory pagetable

From Jerome Glisse
015a02ea12ac2be3e53431b763a531c54b277c71 in ubuntu 3.8
3813f5ca9ab7a00e80a17aab34f155453c66c78a in mainline linux

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