[PECOFF] Skip sections with LNK_INFO.

According to the PE/COFF spec, a section with IMAGE_SCN_LNK_INFO should only
appear in an object file, and not allowed in an executable. So I believe
treating it as the same way as IMAGE_SCN_LNK_INFO is the right thing.

git-svn-id: https://llvm.org/svn/llvm-project/lld/trunk@195692 91177308-0d34-0410-b5e6-96231b3b80d8