[SystemZ] Fix InitMCCodeGenInfo call

createSystemZMCCodeGenInfo was not passing the optimization level to
InitMCCodeGenInfo(), so -O0 would be ignored.  Fixes DebugInfo/namespace.ll
after the changes in r181271.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@181312 91177308-0d34-0410-b5e6-96231b3b80d8