[X86] Use getAllOnesConstant instead of getConstant(-1). NFC (llvm#114299)

Author: topperc

llvm/lib/Target/X86/X86ISelLowering.cpp

@@ -49321,7 +49321,7 @@ static SDValue combineVectorShiftImm(SDNode *N, SelectionDAG &DAG,
   if (!LogicalShift && ISD::isBuildVectorAllOnes(N0.getNode()))
     // N0 is all ones or undef. We guarantee that the bits shifted into the
     // result are all ones, not undef.
-    return DAG.getConstant(-1, SDLoc(N), VT);
+    return DAG.getAllOnesConstant(SDLoc(N), VT);
 
   auto MergeShifts = [&](SDValue X, uint64_t Amt0, uint64_t Amt1) {
     unsigned NewShiftVal = Amt0 + Amt1;