[XCore] Add missing u6 / lu6 instructions.

These instructions are not targeted by the compiler but they are
needed for the MC layer.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@175403 91177308-0d34-0410-b5e6-96231b3b80d8
[XCore] Add missing u10 / lu10 instructions.

These instructions are not targeted by the compiler but they are
needed for the MC layer.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@175404 91177308-0d34-0410-b5e6-96231b3b80d8