Debug Info: code clean up.

Remove the unneeded return values from createMemberDIE, constructEnumTypeDIE,
getOrCreateTemplateTypeParameterDIE, and getOrCreateTemplateValueParameterDIE.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@193285 91177308-0d34-0410-b5e6-96231b3b80d8