[Comgr][CMake] Add a CMake option COMGR_DISABLE_SPIRV

Before it was just a local CMake variable that did not end up in
CMakeCache.txt.

Change-Id: I65d2c6b5e0062af25efbff3a73067a5f54702747

Author: jmmartinez

amd/comgr/CMakeLists.txt

@@ -166,8 +166,9 @@ set(AMD_COMGR_PRIVATE_COMPILE_DEFINITIONS ${LLVM_DEFINITIONS})
 set(AMD_COMGR_PUBLIC_LINKER_OPTIONS)
 set(AMD_COMGR_PRIVATE_LINKER_OPTIONS)
 
+option(COMGR_DISABLE_SPIRV "To disable SPIRV in Comgr" OFF)
 if(${COMGR_DISABLE_SPIRV})
-  list(APPEND AMD_COMGR_PRIVATE_COMPILE_OPTIONS "-DCOMGR_DISABLE_SPIRV")
+    list(APPEND AMD_COMGR_PRIVATE_COMPILE_DEFINITIONS "COMGR_DISABLE_SPIRV")
 endif()
 
 list(APPEND AMD_COMGR_PRIVATE_COMPILE_OPTIONS "-DAMD_COMGR_GIT_COMMIT=${AMD_COMGR_GIT_COMMIT}")