intel: xglQueueWaitIdle() should wait for presents

Make intel_queue own a intel_fence that is automatically updated by
xglQueueSubmit() and xglQueuePresent().  Make xglQueueWaitIdle() call
intel_fence_wait() on the fence.
diff --git a/icd/intel/fence.h b/icd/intel/fence.h
index 66f066a..b16b526 100644
--- a/icd/intel/fence.h
+++ b/icd/intel/fence.h
@@ -59,6 +59,9 @@
 
 XGL_RESULT intel_fence_wait(struct intel_fence *fence, int64_t timeout_ns);
 
+void intel_fence_copy(struct intel_fence *fence,
+                      const struct intel_fence *src);
+
 void intel_fence_set_seqno(struct intel_fence *fence,
                            struct intel_bo *seqno_bo);