[ELF] Fix comments.

The comments in the files that described the file name as part of each file
header ran over 80 columns, which clang-format split over multiple lines.

This commit fixes to make them appear properly.

git-svn-id: https://llvm.org/svn/llvm-project/lld/trunk@200181 91177308-0d34-0410-b5e6-96231b3b80d8