Fix code that assumes the register info will be dumped into a target

Fix code that assumes the register info will be dumped into a target
namespace instead of the reg class namespace.  Update getRegClassForType()
to use modified names due to tblgen change.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@22923 91177308-0d34-0410-b5e6-96231b3b80d8