[MIPS] Move MIPS ABI flags structure constants to the separate header

http://reviews.llvm.org/D9517

The separate header file allows to reuse the MIPS ABI flags structure
constants in other LLVM tools like the llvm-readobj.

No functional changes.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@236732 91177308-0d34-0410-b5e6-96231b3b80d8
3 files changed