drm/radeon/kms: only evict to GTT if CP is ready

Testing GTT ready might be more correct but cp.ready
works fine and has been tested on irc by 2-3 ppl.

fixes bug k.org 15035 and fd.o 25733
Signed-off-by: Dave Airlie <airlied@redhat.com>

drivers/gpu/drm/radeon/radeon_ttm.c

@@ -215,6 +215,9 @@ static void radeon_evict_flags(struct ttm_buffer_object *bo,
 	rbo = container_of(bo, struct radeon_bo, tbo);
 	switch (bo->mem.mem_type) {
 	case TTM_PL_VRAM:
+		if (rbo->rdev->cp.ready == false)
+			radeon_ttm_placement_from_domain(rbo, RADEON_GEM_DOMAIN_CPU);
+		else
 			radeon_ttm_placement_from_domain(rbo, RADEON_GEM_DOMAIN_GTT);
 		break;
 	case TTM_PL_TT: