Forward fix of forward only ops

Differential Revision: D84155460

Pull Request resolved: #533

Author: xuzhao9

tritonbench/operators/decoding_attention/operator.py

@@ -277,6 +277,7 @@ class Operator(BenchmarkOperator):
     DEFAULT_PRECISION = "bf16"
 
     DEFAULT_METRICS = ["latency", "speedup"]
+    FWD_ONLY = True
 
     def __init__(
         self, tb_args: argparse.Namespace, extra_args: Optional[List[str]] = None