PR #13058: Use `BufferF32` instead of `Buffer` in GPU FFI example
PR #13058: Use `BufferF32` instead of `Buffer` in GPU FFI example

Imported from GitHub PR https://github.com/openxla/xla/pull/13058


Copybara import of the project:

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5db8e9ecb4becd69cab0381c5142058697afadb5 by Andrey Portnoy <aportnoy@nvidia.com>:

Use `BufferF32` instead of `Buffer` in GPU FFI example

Merging this change closes #13058

FUTURE_COPYBARA_INTEGRATE_REVIEW=https://github.com/openxla/xla/pull/13058 from openxla:aportnoy/fix-ffi-docs-buffer 5db8e9ecb4becd69cab0381c5142058697afadb5
