cmake: fix CMP0194 warning on Windows with MSVC (llama/21630)

cmake: fix CMP0194 warning on Windows with MSVC (llama/21630)

* cmake: fix CMP0194 warning on Windows with MSVC

Set CMP0194 policy to NEW before project() call in ggml/CMakeLists.txt to suppress the "MSVC is not an assembler for language ASM" warning introduced in CMake 4.1.

The ggml project enables ASM globally for Metal (macOS) and KleidiAI (ARM) backends. On Windows/MSVC, no assembler sources are used, but CMake 4.1+ warns because cl.exe is not a valid ASM compiler.

This follows the same pattern used in ggml-vulkan (CMP0114, CMP0147).

Closes ggml-org/llama.cpp#20311

* cmake: apply cisc's formatting suggestion

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Co-authored-by: texasich <redacted>