i965: Set the GEM domain flags for the scratch space.

They go into the render cache, so while we don't care about their
contents after execution, failing to note them could cause the writes
to be flushed over important buffer contents later.

src/mesa/drivers/dri/i965/brw_wm_state.c

@@ -222,7 +222,7 @@ wm_unit_create_from_key(struct brw_context *brw, struct brw_wm_unit_key *key,
       drm_intel_bo_emit_reloc(bo, offsetof(struct brw_wm_unit_state, thread2),
 			      brw->wm.scratch_bo,
 			      wm.thread2.per_thread_scratch_space,
-			      0, 0);
+			      I915_GEM_DOMAIN_RENDER, I915_GEM_DOMAIN_RENDER);
    }
 
    /* Emit sampler state relocation */