[NFC] Trivial fix to silence linter (Dao-AILab#1928)

Not much to see here, but this causes linter noise

Author: jduprat

csrc/flash_attn/flash_api.cpp

@@ -1340,7 +1340,7 @@ mha_fwd_kvcache(at::Tensor &q,                 // batch_size x seqlen_q x num_he
                      /*cu_seqlens_q_d=*/nullptr,
                      /*cu_seqlens_k_d=*/nullptr,
                      /*seqused_k=*/nullptr,
-                     /*p_ptr=*/nullptr,
+                     /*p_d=*/nullptr,
                      softmax_lse.data_ptr(),
                      /*p_dropout=*/0.f,
                      softmax_scale,