[llvm-readobj] Add GNU style dumper for .gnu.version section

Summary: Currently, `llvm-readobj` do not support GNU style dumper for symbol versioning sections. In this patch, I would like to implement dumper for `.gnu.version` section

Reviewers: jhenderson, rupprecht, grimar

Reviewed By: jhenderson, rupprecht

Subscribers: llvm-commits

Tags: #llvm

Differential Revision: https://reviews.llvm.org/D59877

llvm-svn: 357578