MIPS: Add maddv/msubv MSA instructions

Added maddv.df, msubv.df, fmadd.df and fmsub.df MSA instructions
in assembler, disassembler and tests.

These instructions are needed for multiplyaccumulate support in
ART Vectorizer.

Test: mma test-art-host-gtest

Change-Id: Idef7faaeed47f1fef83fa58676ce664afe24ffe8
7 files changed