[Ops] Add layernorm for qwen3Next (#5765)

### What this PR does / why we need it?
Add layernormFn triton op for qwen3Next model for better performance.

<img width="248" height="526" alt="image"
src="https://github.com/user-attachments/assets/27b47157-5df5-4db1-aa88-1dae799b2bf6"
/>

### Does this PR introduce _any_ user-facing change?

No

### How was this patch tested?

- vLLM version: v0.13.0
- vLLM main:
2f4e6548ef

---------

Signed-off-by: SunnyLee219 <3294305115@qq.com>

vllm_ascend/utils.py

@@ -669,7 +669,7 @@ def register_ascend_customop(vllm_config: VllmConfig | None = None):
 
     from vllm_ascend.ops.activation import AscendQuickGELU, AscendSiluAndMul
     from vllm_ascend.ops.fused_moe.fused_moe import AscendFusedMoE, AscendSharedFusedMoE
-    from vllm_ascend.ops.layernorm import AscendGemmaRMSNorm, AscendRMSNorm
+    from vllm_ascend.ops.layernorm import AscendGemmaRMSNorm, AscendRMSNorm, AscendRMSNormGated
     from vllm_ascend.ops.linear import (
         AscendColumnParallelLinear,
         AscendMergedColumnParallelLinear,
@@ -715,6 +715,7 @@ def register_ascend_customop(vllm_config: VllmConfig | None = None):
         "MultiHeadLatentAttentionWrapper": AscendMultiHeadLatentAttention,
         "MMEncoderAttention": AscendMMEncoderAttention,
         "ApplyRotaryEmb": AscendApplyRotaryEmb,
+        "RMSNormGated": AscendRMSNormGated,
     }
 
     # 310P: override selected ops with 310P implementations (keep minimal changes outside _310p)