[AMD] Fused qk rmsnorm bf16 for amd/Kimi-K2.5-MXFP4 (#23186)

Co-authored-by: Claude Sonnet 4.6 <noreply@anthropic.com>

python/sglang/srt/models/deepseek_common/attention_forward_methods/forward_mla.py

@@ -60,6 +60,9 @@ if _is_cuda:
 
 
 if _use_aiter:
+    from aiter.ops.fused_qk_norm_rope_cache_quant import (
+        fused_qk_rmsnorm as fused_qk_rmsnorm_bf16,
+    )
     from aiter.ops.triton.batched_gemm_a8w8_a_per_token_group_prequant_w_per_batched_tensor_quant import (
         batched_gemm_a8w8_a_per_token_group_prequant_w_per_batched_tensor_quant,
     )
@@ -160,6 +163,15 @@ class DeepseekMLAForwardMixin:
                                 output_unquantized_inp1=False,
                             )
 
+                    elif _use_aiter:
+                        q, k_nope = fused_qk_rmsnorm_bf16(
+                            q,
+                            self.q_a_layernorm.weight,
+                            self.q_a_layernorm.variance_epsilon,
+                            k_nope,
+                            self.kv_a_layernorm.weight,
+                            self.kv_a_layernorm.variance_epsilon,
+                        )
                     else:
                         q = self.q_a_layernorm(q)
                         k_nope = self.kv_a_layernorm(k_nope)