readelf: report all relocation types in rel/rela for MIPS N64

[emaste]

Summary

The 64-bit MIPS N64 ABI includes three relocation types in one rel or rela entry.

This is rather ugly, but then so is the MIPS ABI. Open to suggestions for handling this in a cleaner way (or just going ahead with this for now and refactoring later).

[emaste]

ELF Tool Chain ticket #532
https://sourceforge.net/p/elftoolchain/tickets/532/

[kaiw]

The patch looks good to me. (although I didn't test it with a MIPS N64 object)

[kaiw]

accept patch

[emaste]

Committed upstream as http://sourceforge.net/p/elftoolchain/code/3478

[brooks]

I don't have a strong opinion how to not stuff MIPS junk into this MI code, but I might suggest making these checks

if (re->ehdr.e_machine == EM_MIPS) {

use a macro or inline function of some sort because I'm going to have to add EM_MIPS_CHERI cases to make them work with CheriABI binaries.