fix comment

Author: Zor-X-L

src/llama.cpp

@@ -1792,7 +1792,7 @@ struct llama_mmap {
                 PVOID VirtualAddress;
                 SIZE_T NumberOfBytes;
             } WIN32_MEMORY_RANGE_ENTRY, *PWIN32_MEMORY_RANGE_ENTRY;
-#endif // (_WIN32_WINNT >= _WIN32_WINNT_WIN8)
+#endif // (_WIN32_WINNT < _WIN32_WINNT_WIN8)
 
             BOOL (WINAPI *pPrefetchVirtualMemory) (HANDLE, ULONG_PTR, PWIN32_MEMORY_RANGE_ENTRY, ULONG);
             HMODULE hKernel32 = GetModuleHandleW(L"kernel32.dll");