[llvm] [RISCV] Add LLVM IR intrinsics and codegen for XSfvfexp* and XSfvfexpa* (PR #164499)

[LLVM Continuous Integration via llvm-commits]

llvm-ci wrote:

LLVM Buildbot has detected a new failure on builder `ppc64le-flang-rhel-clang` running on `ppc64le-flang-rhel-test` while building `llvm` at step 6 "test-build-unified-tree-check-flang".

Full details are available at: https://lab.llvm.org/buildbot/#/builders/157/builds/41852

<details>
<summary>Here is the relevant piece of the build log for the reference</summary>

```
Step 6 (test-build-unified-tree-check-flang) failure: 1200 seconds without output running [b'ninja', b'check-flang'], attempting to kill
...
PASS: Flang :: Semantics/typeinfo01.f90 (3940 of 3950)
PASS: Flang :: Semantics/typeinfo05.f90 (3941 of 3950)
PASS: Flang :: Transforms/DoConcurrent/skip_all_nested_loops.f90 (3942 of 3950)
PASS: Flang :: Transforms/DoConcurrent/use_loop_bounds_in_body.f90 (3943 of 3950)
PASS: Flang :: Transforms/tbaa-local-alloc-threshold.fir (3944 of 3950)
PASS: Flang :: Transforms/debug-omp-target-op-1.fir (3945 of 3950)
PASS: Flang :: Transforms/debug-dwarf-version.fir (3946 of 3950)
PASS: Flang :: Lower/OpenMP/rtl-flags.f90 (3947 of 3950)
PASS: Flang :: Driver/omp-driver-offload.f90 (3948 of 3950)
PASS: Flang :: Intrinsics/math-codegen.fir (3949 of 3950)
command timed out: 1200 seconds without output running [b'ninja', b'check-flang'], attempting to kill
process killed by signal 9
program finished with exit code -1
elapsedTime=3210.646674

```

</details>

https://github.com/llvm/llvm-project/pull/164499