[AArch64] Add the Ampere1A core

The Ampere1A core improves on the Ampere1 with key differences being:
 * memory tagging is supported
 * SM3/SM4 are supported
 * adds a new fusion pair for (A+B+1 and A-B-1)
   (added in a later commit)

Depends on D142395

Reviewed By: dmgreen

Differential Revision: https://reviews.llvm.org/D142396