Fix typo in OpenCL type mangling. This is still bogus (we should either use the

actual source name of the typedef or a vendor mangling) but at least it stands
a chance of demangling now.

We would also benefit from some test coverage of this (OpenCL +
__attribute__((overloadable)) is probably required to reach this).


git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@259618 91177308-0d34-0410-b5e6-96231b3b80d8