[llvm] [RISCV] Select add(vec, splat(scalar)) to PADD_*S for P extension (PR #190303)

[LLVM Continuous Integration via llvm-commits]

llvm-ci wrote:

LLVM Buildbot has detected a new failure on builder `llvm-clang-ubuntu-x-aarch64-pauthtest` running on `as-builder-11` while building `llvm` at step 17 "rsync-default-test-suite".

Full details are available at: https://lab.llvm.org/buildbot/#/builders/227/builds/635

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

```
Step 17 (rsync-default-test-suite) failure: cmake (failure)
0.090 [1/1/0] Re-checking globbed directories...
0.167 [0/1/0] cd /home/buildbot/worker/as-builder-11/x-aarch64-pauthtest/build/llvm-test-suite && /home/buildbot/worker/as-builder-11/x-aarch64-pauthtest/llvm-test-suite/utils/rsync.sh ssh buildbot at arm64-linux-02.lab.llvm.org /home/buildbot/worker/as-builder-11/x-aarch64-pauthtest/build/llvm-test-suite
+ ssh buildbot at arm64-linux-02.lab.llvm.org mkdir -p /home/buildbot/worker/as-builder-11/x-aarch64-pauthtest/build/llvm-test-suite
+ eval rsync -a --delete --delete-excluded -e '"ssh"' '--exclude="*.o"' '--exclude="*.a"' '--exclude="*.time"' '--exclude="*.cmake"' --exclude=Output/ --exclude=.ninja_deps --exclude=.ninja_log --exclude=build.ninja --exclude=rules.ninja --exclude=CMakeFiles/ /home/buildbot/worker/as-builder-11/x-aarch64-pauthtest/build/llvm-test-suite/ buildbot at arm64-linux-02.lab.llvm.org:/home/buildbot/worker/as-builder-11/x-aarch64-pauthtest/build/llvm-test-suite/
++ rsync -a --delete --delete-excluded -e ssh '--exclude=*.o' '--exclude=*.a' '--exclude=*.time' '--exclude=*.cmake' --exclude=Output/ --exclude=.ninja_deps --exclude=.ninja_log --exclude=build.ninja --exclude=rules.ninja --exclude=CMakeFiles/ /home/buildbot/worker/as-builder-11/x-aarch64-pauthtest/build/llvm-test-suite/ buildbot at arm64-linux-02.lab.llvm.org:/home/buildbot/worker/as-builder-11/x-aarch64-pauthtest/build/llvm-test-suite/
client_loop: send disconnect: Broken pipe
rsync: [sender] write error: Broken pipe (32)
rsync error: error in socket IO (code 10) at io.c(849) [sender=3.2.7]
FAILED: CMakeFiles/rsync /home/buildbot/worker/as-builder-11/x-aarch64-pauthtest/build/llvm-test-suite/CMakeFiles/rsync 
cd /home/buildbot/worker/as-builder-11/x-aarch64-pauthtest/build/llvm-test-suite && /home/buildbot/worker/as-builder-11/x-aarch64-pauthtest/llvm-test-suite/utils/rsync.sh ssh buildbot at arm64-linux-02.lab.llvm.org /home/buildbot/worker/as-builder-11/x-aarch64-pauthtest/build/llvm-test-suite
ninja: build stopped: subcommand failed.

```

</details>

https://github.com/llvm/llvm-project/pull/190303