Fix CMake Error for Vulkan with LLVM

[hydroo]

Repro/Error:

cd BUILD-release-vulkan-clang
cmake .. --preset x64-windows-llvm-release -B ..\BUILD-release-vulkan-clang -DGGML_VULKAN=1
cmake --build . --config Release

[..]
[29/199] Performing configure step for 'vulkan-shaders-gen'
FAILED: ggml/src/ggml-vulkan/vulkan-shaders-gen-prefix/src/vulkan-shaders-gen-stamp/vulkan-shaders-gen-configure D:/projects/woa/misc/llama.cpp-git/BUILD-release-clang/ggml/src/ggml-vulkan/vulkan-shaders-gen-prefix/src/vulkan-shaders-gen-stamp/vulkan-shaders-gen-configure
C:\Windows\system32\cmd.exe /C "cd /D D:\projects\woa\misc\llama.cpp-git\BUILD-release-clang\ggml\src\ggml-vulkan\vulkan-shaders-gen-prefix\src\vulkan-shaders-gen-build && "C:\Program Files\CMake\bin\cmake.exe" -DCMAKE_TOOLCHAIN_FILE=D:/projects/woa/misc/llama.cpp-git/BUILD-release-clang/host-toolchain.cmake -DCMAKE_INSTALL_PREFIX=D:/projects/woa/misc/llama.cpp-git/BUILD-release-clang -DGGML_VULKAN_COOPMAT_GLSLC_SUPPORT=OFF -DGGML_VULKAN_COOPMAT2_GLSLC_SUPPORT=OFF -DGGML_VULKAN_INTEGER_DOT_GLSLC_SUPPORT=OFF -GNinja -S D:/projects/woa/misc/llama.cpp-git/ggml/src/ggml-vulkan/vulkan-shaders -B D:/projects/woa/misc/llama.cpp-git/BUILD-release-clang/ggml/src/ggml-vulkan/vulkan-shaders-gen-prefix/src/vulkan-shaders-gen-build && "C:\Program Files\CMake\bin\cmake.exe" -E touch D:/projects/woa/misc/llama.cpp-git/BUILD-release-clang/ggml/src/ggml-vulkan/vulkan-shaders-gen-prefix/src/vulkan-shaders-gen-stamp/vulkan-shaders-gen-configure"
-- The C compiler identification is unknown
-- The CXX compiler identification is unknown
CMake Error at CMakeLists.txt:2 (project):
  The CMAKE_C_COMPILER:

    C:/Program

  is not a full path to an existing compiler tool.

  Tell CMake where to find the compiler by setting either the environment
  variable "CC" or the CMake cache entry CMAKE_C_COMPILER to the full path to
  the compiler, or to the compiler name if it is in the PATH.


CMake Error at CMakeLists.txt:2 (project):
  The CMAKE_CXX_COMPILER:

    C:/Program

  is not a full path to an existing compiler tool.

  Tell CMake where to find the compiler by setting either the environment
  variable "CXX" or the CMake cache entry CMAKE_CXX_COMPILER to the full path
  to the compiler, or to the compiler name if it is in the PATH.


-- Configuring incomplete, errors occurred!
ninja: build stopped: subcommand failed.

This patch adds the missing quotes and makes LLVM builds with Vulkan support for ggml compile successfully.