[mips] Fix (dis)assembly of abs.fmt for micromips

These instructions were previously marked as codegen only preventing
them from being assembled as microMIPS or disassembled.

Reviewers: atanasyan, abeserminji

Differential Revision: https://reviews.llvm.org/D39123


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@316656 91177308-0d34-0410-b5e6-96231b3b80d8
5 files changed