[llvm-readobj][ELF] Teach llvm-readobj to show dynamic relocation in REL format

MIPS 32-bit ABI uses REL relocation record format to save dynamic
relocations. The patch teaches llvm-readobj to show dynamic relocations
in this format.

Differential Revision: http://reviews.llvm.org/D16114

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@258001 91177308-0d34-0410-b5e6-96231b3b80d8
3 files changed