[llvm] [RISCV][P-ext] Remove VXSAT from SHL/SHLR/SHA/SHAR. Add to PSAS and PSSA. (PR #195488)

[Kito Cheng via llvm-commits]

https://github.com/kito-cheng approved this pull request.

LGTM, checked with spec :)

https://github.com/llvm/llvm-project/pull/195488