Move DataLayout onto the AArch64 subtarget.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@210552 91177308-0d34-0410-b5e6-96231b3b80d8
Remove caching of the subtarget for AArch64SelectionDAGInfo.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@210553 91177308-0d34-0410-b5e6-96231b3b80d8
Have AArch64SelectionDAGInfo take a DataLayout parameter rather
than a TargetMachine.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@210554 91177308-0d34-0410-b5e6-96231b3b80d8