vulkan: fix windows find_package of SPIRV-Headers (ggml-org#23215)

* vulkan: fix windows find_package of SPIRV-Headers

* not windows-only

Author: jeffbolznv

ggml/src/ggml-vulkan/CMakeLists.txt

@@ -8,7 +8,10 @@ endif()
 
 find_package(Vulkan COMPONENTS glslc REQUIRED)
 
-find_package(SPIRV-Headers REQUIRED)
+if (DEFINED ENV{VULKAN_SDK})
+    list(APPEND CMAKE_PREFIX_PATH "$ENV{VULKAN_SDK}")
+endif()
+find_package(SPIRV-Headers CONFIG REQUIRED)
 
 if (CMAKE_CXX_COMPILER_ID STREQUAL "MSVC")
     # Parallel build object files