[yaml2obj] Add support for sh_link via `Link` key.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@184022 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/Object/ELFYAML.cpp b/lib/Object/ELFYAML.cpp
index 6e99767..e0e95be 100644
--- a/lib/Object/ELFYAML.cpp
+++ b/lib/Object/ELFYAML.cpp
@@ -267,6 +267,7 @@
   IO.mapOptional("Flags", Section.Flags, ELFYAML::ELF_SHF(0));
   IO.mapOptional("Address", Section.Address, Hex64(0));
   IO.mapOptional("Content", Section.Content);
+  IO.mapOptional("Link", Section.Link);
   IO.mapOptional("AddressAlign", Section.AddressAlign, Hex64(0));
 }