[mips] Move MipsCCState to a separate file and clang-formatted it.

Summary: Depends on D6113

Reviewers: theraven, vmedic

Reviewed By: vmedic

Subscribers: llvm-commits

Differential Revision: http://reviews.llvm.org/D6114

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@221525 91177308-0d34-0410-b5e6-96231b3b80d8