[llvm][CodeGen][aarch64] Add contiguous prefetch intrinsics for SVE.

Summary: The patch covers both register/register and register/immediate addressing modes.

Reviewers: efriedma, andwar, sdesmalen

Reviewed By: sdesmalen

Subscribers: sdesmalen, tschuett, kristof.beyls, hiraditya, rkruppe, psnobl, llvm-commits

Tags: #llvm

Differential Revision: https://reviews.llvm.org/D74581