[AArch64] When creating MRS instruction, make sure the destination register is
declared as a definition.

This fixes the machine verifier error for CodeGen/AArch64/nzcv-save.ll.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@267185 91177308-0d34-0410-b5e6-96231b3b80d8
2 files changed