[clang] [Hexagon] Refactor HVX target feature addition(NFC) (PR #182073)

[Brian Cain via cfe-commits]

================
@@ -812,3 +795,32 @@ StringRef HexagonToolChain::GetTargetCPUVersion(const ArgList &Args) {
   CPU.consume_front("hexagon");
   return CPU;
 }
+
+std::string HexagonToolChain::GetHVXVersion(const ArgList &Args, bool &HasHVX) {
----------------
androm3da wrote:

You can return a `std::optional<std::string>` instead of passing `&HasHVX`.

https://github.com/llvm/llvm-project/pull/182073