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.c b/icd/intel/fence.c
index b19cabd..41eda9b 100644
--- a/icd/intel/fence.c
+++ b/icd/intel/fence.c
@@ -74,6 +74,13 @@
     intel_base_destroy(&fence->obj.base);
 }
 
+void intel_fence_copy(struct intel_fence *fence,
+                      const struct intel_fence *src)
+{
+    intel_wsi_fence_copy(fence, src);
+    intel_fence_set_seqno(fence, src->seqno_bo);
+}
+
 void intel_fence_set_seqno(struct intel_fence *fence,
                            struct intel_bo *seqno_bo)
 {