NXP backend: Update user guide and docs Readme (#14852)

### Summary
This PR updates NXP backend Readmes in backend and examples directories.

### Test plan
-

cc @robert-kalmar @JakeStevens @digantdesai

(cherry picked from commit 41b061e)

Author: roman-janik-nxp

backends/nxp/README.md

@@ -15,6 +15,8 @@ networks, as well as the ability to adapt and scale to new model architectures,
 to AI workloads. ML application development with the eIQ Neutron NPU is fully supported by the 
 [eIQ machine learning software development environment](https://www.nxp.com/design/design-center/software/eiq-ml-development-environment/eiq-toolkit-for-end-to-end-model-development-and-deployment:EIQ-TOOLKIT).
 The eIQ AI SW Stack provides a streamlined development experience for developers and end-users of NXP products.
+eIQ extensions connect broader AI ecosystems to the edge, such as the NVIDIA TAO extension, which enables developers 
+to bring AI models trained and fine-tuned with TAO to NXP-powered edge devices.
 
 
 ## Supported NXP platforms

examples/nxp/README.md

@@ -4,11 +4,11 @@ format and delegate the model computation to eIQ Neutron NPU using the eIQ Neutr
 
 ## Layout
 * `experimental/` - contains CifarNet model example.
-* `models` - demo models instantiation used in examples
+* `models` - various example models.
 * `aot_neutron_compile.py` - script with end-to-end ExecuTorch AoT Neutron Backend workflow.
 * `README.md` - this file.
-* `run_aot_example.sh` - utility script to launch _aot_neutron_compile.py_. Primarily for CI purpose.
-* `setup.sh` - setup script to install NeutronBackend dependencies.
+* `run_aot_example.sh` - utility script for aot_neutron_compile.py.
+* `setup.sh` - setup script for Neutron Converter installation.
 
 ## Setup
 Please finish tutorial [Setting up ExecuTorch](https://pytorch.org/executorch/main/getting-started-setup).
@@ -36,11 +36,11 @@ The steps are expected to be executed from the `executorch` root folder.
 1. Run the `aot_neutron_compile.py` example with the `cifar10` model 
     ```commandline
     $ python -m examples.nxp.aot_neutron_compile --quantize \
-        --delegate --neutron_converter_flavor SDK_25_06 -m cifar10 
+        --delegate --neutron_converter_flavor SDK_25_09 -m cifar10 
     ```
 
 2. It will generate you `cifar10_nxp_delegate.pte` file which can be used with the MCUXpresso SDK `cifarnet_example` 
 project, presented [here](https://mcuxpresso.nxp.com/mcuxsdk/latest/html/middleware/eiq/executorch/docs/nxp/topics/example_applications.html#how-to-build-and-run-executorch-cifarnet-example).
 This project will guide you through the process of deploying your PTE model to the device.
 To get the MCUXpresso SDK follow this [guide](https://mcuxpresso.nxp.com/mcuxsdk/latest/html/middleware/eiq/executorch/docs/nxp/topics/getting_mcuxpresso.html),
-use the MCUXpresso SDK v25.06.00. 
+use the MCUXpresso SDK v25.09.00.