`saa` and `saad` are 32-bit and 64-bit store atomic add instructions.
memory[base] = memory[base] + rt
These instructions are available for "Octeon+" CPU. The patch adds support
for both instructions to MIPS assembler and diassembler and introduces new
CPU type - "octeon+".
Next patches will implement `.set arch=octeon+` directive and `AFL_EXT_OCTEONP`
ISA extension flag support.
Differential Revision: https://reviews.llvm.org/D69849
Simon Atanasyan