RelocVisitor::visit(): Set hasError in the default path.
Object/RelocVisitor: Add minimal support, R_PPC64_ADDR32, for ppc64.

It fixes llvm-dwarfdump for ppc64-elf.
Object/RelocVisitor: Add minimal support, R_MIPS_32, for mips.

It fixes llvm-dwarfdump for mips and mipsel.