r600g,radeonsi: disable fast clear if render condition is on
For some reason, CP DMA doesn't follow the predicate bit if I enable it, so this is the only option. This fixes piglit: spec/NV_conditional_render/clear Cc: mesa-stable@lists.freedesktop.org Reviewed-by:Michel Dänzer <michel.daenzer@amd.com> (cherry picked from commit bf701a84)