Delete MCRelocationInfo::createExprForRelocation.

This method has no callers.

Also remove X86ELFRelocationInfo.cpp and X86MachORelocationInfo.cpp
which only existed to provide an implementation of that method.

Ok'd by Rafael and Jim.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@257859 91177308-0d34-0410-b5e6-96231b3b80d8
7 files changed