[clang] [RISCV] Minor improvements/cleanup to target attribute handling. NFC (PR #73851)

[Craig Topper via cfe-commits]

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@@ -265,11 +264,11 @@ resolveTargetAttrOverride(const std::vector<std::string> &FeaturesVec,
   if (I == FeaturesVec.end())
     return FeaturesVec;
 
-  const std::vector<std::string> FeaturesNeedOverride(FeaturesVec.begin(), I);
+  ArrayRef<std::string> FeaturesNeedOverride(&*FeaturesVec.begin(), &*I);
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topperc wrote:

The `&*` are here to convert from the std::vector pointer wrappers to raw pointers.

https://github.com/llvm/llvm-project/pull/73851