[DOC][CC] Only IR model is supported by CC for now, other model forma…

…t need to convert to IR first for enabling CC (openvinotoolkit#25448)

### Details:
 - Modify the dev doc for cc limitation.

### Tickets:
 - *CVS-136255*

---------

Signed-off-by: Zhai, Xuejun <xuejun.zhai@intel.com>
Co-authored-by: Chen Peter <peter.chen@intel.com>

docs/dev/conditional_compilation.md

@@ -77,6 +77,7 @@ The differences are only in the code usage analysis step. The analysis step shou
 ## Limitations
 
 * Currently, Ninja build system is not supported for the conditional compilation build.
+* Currently, conditional compilation supports OpenVINO IR models only. To enable conditional compilation, the models from alternative frameworks (PyTorch, TensorFlow, ONNX, etc.) need to be converted to OpenVINO IR models first.
 
 ## See also
  * [OpenVINO™ README](../../README.md)