De-constify pointers to Type since they can't be modified. NFC

This was already done in most places a while ago. This just fixes the ones that crept in over time.

llvm-svn: 243842
diff --git a/llvm/lib/Analysis/VectorUtils.cpp b/llvm/lib/Analysis/VectorUtils.cpp
index 67f68dc..1ebff0f 100644
--- a/llvm/lib/Analysis/VectorUtils.cpp
+++ b/llvm/lib/Analysis/VectorUtils.cpp
@@ -283,7 +283,7 @@
 /// strides "a[i*stride]". Returns the symbolic stride, or null otherwise.
 llvm::Value *llvm::getStrideFromPointer(llvm::Value *Ptr, ScalarEvolution *SE,
                                         Loop *Lp) {
-  const PointerType *PtrTy = dyn_cast<PointerType>(Ptr->getType());
+  auto *PtrTy = dyn_cast<PointerType>(Ptr->getType());
   if (!PtrTy || PtrTy->isAggregateType())
     return nullptr;