[RISCV] Fix obvious copy paste error.

CASE_VFMA_OPCODE_VV and CASE_VFMA_CHANGE_OPCODE_VV need to match up if we are
are to avoid "Unexpected opcode" errors, but in CASE_VFMA_CHANGE_OPCODE_VV,
CASE_VFMA_CHANGE_OPCODE_LMULS_MF2 had mistakenly been used instead of
CASE_VFMA_CHANGE_OPCODE_LMULS_MF4.

llvm/lib/Target/RISCV/RISCVInstrInfo.cpp

@@ -3016,7 +3016,7 @@ bool RISCVInstrInfo::findCommutedOpIndices(const MachineInstr &MI,
   CASE_VFMA_CHANGE_OPCODE_LMULS_M1(OLDOP, NEWOP, TYPE, SEW)
 
 #define CASE_VFMA_CHANGE_OPCODE_VV(OLDOP, NEWOP)                               \
-  CASE_VFMA_CHANGE_OPCODE_LMULS_MF2(OLDOP, NEWOP, VV, E16)                     \
+  CASE_VFMA_CHANGE_OPCODE_LMULS_MF4(OLDOP, NEWOP, VV, E16)                     \
   CASE_VFMA_CHANGE_OPCODE_LMULS_MF2(OLDOP, NEWOP, VV, E32)                     \
   CASE_VFMA_CHANGE_OPCODE_LMULS_M1(OLDOP, NEWOP, VV, E64)