correct LLVMRustCreateThinLTOData arg types

Author: klensy

compiler/rustc_llvm/llvm-wrapper/PassWrapper.cpp

@@ -1251,8 +1251,9 @@ getFirstDefinitionForLinker(const GlobalValueSummaryList &GVSummaryList) {
 // here is basically the same as before threads are spawned in the `run`
 // function of `lib/LTO/ThinLTOCodeGenerator.cpp`.
 extern "C" LLVMRustThinLTOData *
-LLVMRustCreateThinLTOData(LLVMRustThinLTOModule *modules, int num_modules,
-                          const char **preserved_symbols, int num_symbols) {
+LLVMRustCreateThinLTOData(LLVMRustThinLTOModule *modules, unsigned num_modules,
+                          const char **preserved_symbols,
+                          unsigned num_symbols) {
   auto Ret = std::make_unique<LLVMRustThinLTOData>();
 
   // Load each module's summary and merge it into one combined index