s/Data/Kind/g. No functionality change.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@173827 91177308-0d34-0410-b5e6-96231b3b80d8
Add a couple of accessor methods to get the kind and values of an attribute.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@173828 91177308-0d34-0410-b5e6-96231b3b80d8