Revert "[PECOFF] Fix atom ordinals."

This reverts commit r195852 because LLD seems to create broken executables
with that patch when compiled with MSVC 2013.

git-svn-id: https://llvm.org/svn/llvm-project/lld/trunk@196078 91177308-0d34-0410-b5e6-96231b3b80d8