[llvm] [llvm-readobj] Dump callgraph section info for ELF (PR #157499)

[Prabhu Rajasekaran via llvm-commits]

Prabhuk wrote:

@ilovepi @jh7370 -- I believe I've addressed all the comments. PTAL. Thank you. 

https://github.com/llvm/llvm-project/pull/157499