[sve][acle] Add reinterpret intrinsics for brain float.

Reviewers: kmclaughlin, efriedma, ctetreau, sdesmalen, david-arm

Subscribers: tschuett, hiraditya, rkruppe, psnobl, cfe-commits, llvm-commits

Tags: #clang, #llvm

Differential Revision: https://reviews.llvm.org/D82501