[llvm] [Mips] Add support of MipsInstrInfo::getNop() (PR #139863)

[YunQiang Su via llvm-commits]

================
@@ -53,6 +54,13 @@ bool MipsInstrInfo::isZeroImm(const MachineOperand &op) const {
   return op.isImm() && op.getImm() == 0;
 }
 
+MCInst MipsInstrInfo::getNop() const {
+  return MCInstBuilder(Mips::SLL)
----------------
wzssyqa wrote:

Maybe we should try to support micromips?

https://github.com/llvm/llvm-project/pull/139863