[Benchmark] Add cross_entropy to tritonbench integration (#321)

Author: yf225

benchmarks/run.py

@@ -65,6 +65,11 @@
         "examples.attention",
         "attention",
     ),
+    "cross_entropy": (
+        "tritonbench.operators.cross_entropy.operator",
+        "examples.cross_entropy",
+        "cross_entropy",
+    ),
 }