fix 关闭attn sink情况下的错误

csrc/smxx/decode/combine/combine.cu

@@ -86,7 +86,7 @@ flash_fwd_mla_combine_kernel(const CombineParams params) {
         float global_lse = (sum_lse == 0.f || sum_lse == -INFINITY) ? INFINITY : logf(sum_lse) + max_lse;
         if (lane_idx == 0)
             gLse(warp_idx) = global_lse;
-        float o_scale = 0.0f;
+        float o_scale = 1.0f;
         if (params.attn_sink != nullptr) {
             int q_head_idx = h_block_idx*BLOCK_SIZE_M + warp_idx;
             float attn_sink = __ldg(params.attn_sink + q_head_idx);