[RISCV] Add LLVM IR intrinsics and codegen for XSfvfexp* and XSfvfexpa*#164499

mshockwave merged 2 commits intollvm:mainllvm/llvm-project:mainfrom

mshockwave:patch/rvv/xsfvfexp-codegenmshockwave/llvm-project:patch/rvv/xsfvfexp-codegenCopy head branch name to clipboard