[lld][ELF] Fix "enumeral and non-enumeral type in conditional expression" warning (NFC)

GCC warning:
```
/llvm-project/lld/ELF/SyntheticSections.cpp: In member function ‘virtual void lld::elf::VersionTableSection::writeTo(uint8_t*)’:
/llvm-project/lld/ELF/SyntheticSections.cpp:3128:34: warning: enumeral and non-enumeral type in conditional expression [-Wextra]
 3128 |     write16(buf, s.sym->isLazy() ? VER_NDX_GLOBAL : s.sym->versionId);
      |                  ~~~~~~~~~~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
```