[3/3][Clang][RISCV] Add __riscv_ for overloaded intrinsics

This commit adds prefix for the overloaded RVV intrinsics.

This is the 3rd commit of a patch-set to add __riscv_ for all RVV
intrinsics.

This follows the naming guideline under riscv-c-api-doc to add the
`__riscv_` suffix for all RVV intrinsics.

Pull Request:
riscv-non-isa/riscv-c-api-doc#31
riscv-non-isa/rvv-intrinsic-doc#189

Depends on D142644.

Reviewed By: kito-cheng

Differential Revision: https://reviews.llvm.org/D142697

Author: eopXD

clang/lib/Support/RISCVVIntrinsicUtils.cpp

@@ -1005,6 +1005,7 @@ void RVVIntrinsic::updateNamesAndPolicy(bool IsMasked, bool HasPolicy,
   // This follows the naming guideline under riscv-c-api-doc to add the
   // `__riscv_` suffix for all RVV intrinsics.
   Name = "__riscv_" + Name;
+  OverloadedName = "__riscv_" + OverloadedName;
 
   if (IsMasked) {
     if (PolicyAttrs.isTUMUPolicy())