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>