[AArch64] Armv8.2-A: add the crypto extensions

This adds MC support for the crypto instructions that were made optional
extensions in Armv8.2-A (AArch64 only).

Differential Revision: https://reviews.llvm.org/D49370


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@338010 91177308-0d34-0410-b5e6-96231b3b80d8
13 files changed