Fix AttributeError in _mark_nodes_as_annotated when node is None

Author: KevinUW114514

backends/qualcomm/quantizer/rules.py

@@ -29,6 +29,8 @@
 
 def _mark_nodes_as_annotated(nodes: List[Node]):
     for node in nodes:
+        if node is None:
+            continue
         if Q_ANNOTATION_KEY not in node.meta:
             node.meta[Q_ANNOTATION_KEY] = QuantizationAnnotation()
         node.meta[Q_ANNOTATION_KEY]._annotated = True