[Driver][Mips] Remove redundant abstract/override function.

No functional changes.

git-svn-id: http://llvm.org/svn/llvm-project/cfe/trunk@211982 91177308-0d34-0410-b5e6-96231b3b80d8
[Driver][Mips] Remove redundant brackets.

No functional changes.

git-svn-id: http://llvm.org/svn/llvm-project/cfe/trunk@211983 91177308-0d34-0410-b5e6-96231b3b80d8
[Driver][Mips] Fix else-after-return.

No functional changes.

git-svn-id: http://llvm.org/svn/llvm-project/cfe/trunk@211984 91177308-0d34-0410-b5e6-96231b3b80d8