ggml-zendnn : add ZenDNN backend for AMD CPUs (#17690)

* ggml-zennn: add ZenDNN backend support

* ggml-zendnn : address ZenDNN backend review fixes and suggestions

* docs : apply blockquote syntax to ZenDNN docs

---------

Co-authored-by: Manoj Kumar <mkumar@zettabolt.com>

docs/build.md

@@ -495,6 +495,38 @@ llama_new_context_with_model:       CANN compute buffer size =  1260.81 MiB
 
 For detailed info, such as model/device supports, CANN install, please refer to [llama.cpp for CANN](./backend/CANN.md).
 
+## ZenDNN
+
+ZenDNN provides optimized deep learning primitives for AMD EPYC™ CPUs. It accelerates matrix multiplication operations for inference workloads.
+
+### Compilation
+
+- Using `CMake` on Linux (automatic build):
+
+    ```bash
+    cmake -B build -DGGML_ZENDNN=ON
+    cmake --build build --config Release
+    ```
+
+    The first build will automatically download and build ZenDNN, which may take 5-10 minutes. Subsequent builds will be much faster.
+
+- Using `CMake` with custom ZenDNN installation:
+
+    ```bash
+    cmake -B build -DGGML_ZENDNN=ON -DZENDNN_ROOT=/path/to/zendnn/install
+    cmake --build build --config Release
+    ```
+
+### Testing
+
+You can test with:
+
+```bash
+./build/bin/llama-cli -m PATH_TO_MODEL -p "Building a website can be done in 10 steps:" -n 50
+```
+
+For detailed information about hardware support, setup instructions, and performance optimization, refer to [llama.cpp for ZenDNN](./backend/ZenDNN.md).
+
 ## Arm® KleidiAI™
 KleidiAI is a library of optimized microkernels for AI workloads, specifically designed for Arm CPUs. These microkernels enhance performance and can be enabled for use by the CPU backend.