[doc] update description for dynamic quantization (#33466)

### Details:
 - Updated description for dynamic quantization

Author: isanghao

docs/articles_en/openvino-workflow-generative/inference-with-optimum-intel.rst

@@ -239,7 +239,14 @@ includes **Dynamic quantization** of activations of 4/8-bit quantized MatMuls an
   insignificant deviation in generation accuracy.  Quantization is performed in a group-wise
   manner, with configurable group size. It means that values in a group share quantization
   parameters. Larger group sizes lead to faster inference but lower accuracy. Recommended
-  group size values are ``0``, ``32``, ``64``, or ``128``.
+  group size values are ``0``, ``32``, ``64``, ``128`` or ``-1``(per-token).
+
+  .. note::
+
+   The dynamic quantization group size is treated as a guideline rather than a strict requirement.
+   The actual policy may vary depending on functional capabilities or performance and accuracy considerations.
+   The plugin may choose to disable dynamic quantization entirely or use a smaller group size than the one
+   specified by the user.
 
   On Intel CPU and Intel GPU, dynamic quantization is enabled **by default**.