Cleanup tl.constexpr HAS_ATTN_SCALE

Summary:
X-link: facebookresearch/generative-recommenders#110

X-link: pytorch/benchmark#2531

Reviewed By: LinjianMa

Differential Revision: D65366330

fbshipit-source-id: 43be8c6a04a8751749c35cd18f79a92046e5d36b

Author: hanli0612

tritonbench/operators/ragged_attention/hstu.py

@@ -135,7 +135,6 @@ def forward(
             "BLOCK_D_Q": DimQ,
             "BLOCK_D_V": DimV,
             "max_attn_len": 0,
-            "HAS_MAX_ATTN_LEN": False,
             "HAS_CONTEXTUAL_SEQ_LEN": False,
             "contextual_seq_len": 0,
             "HAS_SORT_BY_LENGTH_INDICES": False,