[Intel GPU] DeepSeek V4 10/N : Add sqrtsoftplus support to fused_topk_torch_native (#28048)

Signed-off-by: Rahul Vijayaraghavan <rahul.vijayaraghavan@intel.com>
Signed-off-by: P V R K Jyothendra Varma <polisetty.v.r.k.jyothendra.varma@intel.com>
Co-authored-by: Rahul Vijayaraghavan <rahul.vijayaraghavan@intel.com>
Co-authored-by: Ma Mingfei <mingfei.ma@intel.com>

python/sglang/srt/layers/moe/topk.py

@@ -652,6 +652,8 @@ def fused_topk_torch_native(
             return gating_output.softmax(dim=-1)
         elif scoring_func == "sigmoid":
             return gating_output.sigmoid()
+        elif scoring_func == "sqrtsoftplus":
+            return F.softplus(gating_output).sqrt()
         else:
             raise ValueError(f"Invalid scoring function: {scoring_func}")