[Analysis] Remove a redundant cast (NFC) (#168184)

NumElts is alreadyof type int.

Identified with readability-redundant-casting.

Author: kazutakahirata

llvm/lib/Analysis/VectorUtils.cpp

@@ -494,7 +494,7 @@ bool llvm::isMaskedSlidePair(ArrayRef<int> Mask, int NumElts,
   for (auto [i, M] : enumerate(Mask)) {
     if (M < 0)
       continue;
-    int Src = M >= (int)NumElts;
+    int Src = M >= NumElts;
     int Diff = (int)i - (M % NumElts);
     bool Match = false;
     for (int j = 0; j < 2; j++) {