[CodeGen] Don't print register classes in -debug output

Since register classes and banks are already printed with the register
definition, don't print it at the end of every instruction anymore.

This follows MIR in this regard and is another step to the unification
of the two formats.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@322086 91177308-0d34-0410-b5e6-96231b3b80d8
9 files changed