[Benchmark] Add softmax tritonbench integration

stack-info: PR: #286, branch: yf225/stack/17

Author: yf225

benchmarks/run.py

@@ -69,6 +69,11 @@
         "examples.fp8_attention",
         "fp8_attention_tritonbench",
     ),
+    "softmax": (
+        "tritonbench.operators.softmax.operator",
+        "examples.softmax",
+        "softmax",
+    ),
 }