(Const)?MIOperands is equivalent to the C++ style
MachineInstr::mop_iterator. Use the latter for consistency except for a
few callers of MIOperands::analyzePhysReg().
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@285029 91177308-0d34-0410-b5e6-96231b3b80d8