CUDA : Update CCCL-tag for 3.2 to final release from RC (#19486)

CCCL 3.2 has been released since it was added to llama.cpp as part of
the backend-sampling PR, and it makes sense to update from RC to final
released version.

https://github.com/NVIDIA/cccl/releases/tag/v3.2.0

ggml/src/ggml-cuda/CMakeLists.txt

@@ -64,7 +64,7 @@ if (CUDAToolkit_FOUND)
         FetchContent_Declare(
             CCCL
             GIT_REPOSITORY https://github.com/nvidia/cccl.git
-            GIT_TAG        v3.2.0-rc2
+            GIT_TAG        v3.2.0
             GIT_SHALLOW    TRUE
         )