[Sync] Update mxfp4.py (20250827) (#9724)

Co-authored-by: github-actions[bot] <github-actions[bot]@users.noreply.github.com>
Co-authored-by: Shiyang Chen <shiyang@x.ai>

python/sglang/srt/layers/quantization/mxfp4.py

@@ -66,10 +66,15 @@ _is_hip = is_hip()
 
 if _is_hip:
     # import aiter
+    try:
         from aiter import ActivationType, QuantType, dtypes
         from aiter.fused_moe import fused_moe
         from aiter.ops.triton.quant import dynamic_mxfp4_quant
         from aiter.utility.fp4_utils import e8m0_shuffle
+    except ImportError as err:
+        ActivationType = QuantType = dtypes = fused_moe = dynamic_mxfp4_quant = (
+            e8m0_shuffle
+        ) = err
 
 
 def _swizzle_mxfp4(quant_tensor, scale, num_warps):