[llvm-objcopy] Allow 'protected' visibility to be set when using
add-symbol

Reviewers: Maskray, rupprecht

Differential Revision: https://reviews.llvm.org/D65891

llvm-svn: 368982
diff --git a/llvm/docs/CommandGuide/llvm-objcopy.rst b/llvm/docs/CommandGuide/llvm-objcopy.rst
index 64ba094..044293c 100644
--- a/llvm/docs/CommandGuide/llvm-objcopy.rst
+++ b/llvm/docs/CommandGuide/llvm-objcopy.rst
@@ -160,6 +160,7 @@
  - `weak` = the symbol will have weak binding.
  - `default` = the symbol will have default visibility.
  - `hidden` = the symbol will have hidden visibility.
+ - `protected` = the symbol will have protected visibility.
  - `file` = the symbol will be an `STT_FILE` symbol.
  - `section` = the symbol will be an `STT_SECTION` symbol.
  - `object` = the symbol will be an `STT_OBJECT` symbol.