[Object][ELF] Test unknown type.

llvm-svn: 226943
diff --git a/llvm/lib/Object/ELFYAML.cpp b/llvm/lib/Object/ELFYAML.cpp
index 7e35fb5..14aa831 100644
--- a/llvm/lib/Object/ELFYAML.cpp
+++ b/llvm/lib/Object/ELFYAML.cpp
@@ -30,6 +30,7 @@
   ECase(ET_DYN)
   ECase(ET_CORE)
 #undef ECase
+  IO.enumFallback<Hex16>(Value);
 }
 
 void