[RISCV][Clang] Add RVV merge intrinsic functions.

Authored-by: Roger Ferrer Ibanez <rofirrim@gmail.com>
Co-Authored-by: Zakk Chen <zakk.chen@sifive.com>

Reviewed By: craig.topper

Differential Revision: https://reviews.llvm.org/D99963

GitOrigin-RevId: 07c3854a75bcbb7521f27e1e775bc79f4d0340f7
3 files changed