Have MSP430SelectionDAGInfo constructor take a DataLayout rather
than a target machine since it doesn't need anything past the
DataLayout.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@211826 91177308-0d34-0410-b5e6-96231b3b80d8
Remove unnecessary caching of variables by MSP430TargetLowering and
make the constructor more general since it only needs a target
machine.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@211827 91177308-0d34-0410-b5e6-96231b3b80d8