[RISCV][NFC] Add missed // clang-format on

clang-format was turned off for the defines, but there was no matching
`// clang-format on` comment at the end. Ran into this in llvm#137973

Author: asb

llvm/lib/Target/RISCV/RISCVInstrInfo.cpp

@@ -3737,6 +3737,7 @@ bool RISCVInstrInfo::findCommutedOpIndices(const MachineInstr &MI,
   CASE_VFMA_CHANGE_OPCODE_LMULS_MF4(OLDOP, NEWOP, VFPR16, E16)                 \
   CASE_VFMA_CHANGE_OPCODE_LMULS_MF2(OLDOP, NEWOP, VFPR32, E32)                 \
   CASE_VFMA_CHANGE_OPCODE_LMULS_M1(OLDOP, NEWOP, VFPR64, E64)
+// clang-format on
 
 MachineInstr *RISCVInstrInfo::commuteInstructionImpl(MachineInstr &MI,
                                                      bool NewMI,