[mips] Use register operands instead of register classes in DSP instruction
definitions.



git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@188343 91177308-0d34-0410-b5e6-96231b3b80d8
[mips] Fix bug in parsing accumulator registers.



git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@188344 91177308-0d34-0410-b5e6-96231b3b80d8