Fix mismerge in CHERI LLVM SelectionDAG::getMemset

The upstream code assumes AS0 for Dst (but curiously not Src), but the
fix for that got lost in CHERI LLVM. Presumably it only affects Morello
LLVM because it has improved libcall detection.

Fixes: 96a072e ("[SelectionDAG] Handle bzero/memset libcalls globally instead of per target")

llvm/lib/CodeGen/SelectionDAG/SelectionDAG.cpp

@@ -7649,14 +7649,14 @@ SDValue SelectionDAG::getMemset(SDValue Chain, const SDLoc &dl, SDValue Dst,
   // If zeroing out and bzero is present, use it.
   if (SrcIsZero && BzeroName) {
     TargetLowering::ArgListTy Args;
-    Args.push_back(CreateEntry(Dst, Type::getInt8PtrTy(Ctx)));
+    Args.push_back(CreateEntry(Dst, Dst.getValueType().getTypeForEVT(Ctx)));
     Args.push_back(CreateEntry(Size, DL.getIntPtrType(Ctx)));
     CLI.setLibCallee(
         TLI->getLibcallCallingConv(RTLIB::BZERO), Type::getVoidTy(Ctx),
         getExternalFunctionSymbol(BzeroName), std::move(Args));
   } else {
     TargetLowering::ArgListTy Args;
-    Args.push_back(CreateEntry(Dst, Type::getInt8PtrTy(Ctx)));
+    Args.push_back(CreateEntry(Dst, Dst.getValueType().getTypeForEVT(Ctx)));
     Args.push_back(CreateEntry(Src, Src.getValueType().getTypeForEVT(Ctx)));
     Args.push_back(CreateEntry(Size, DL.getIntPtrType(Ctx)));
     CLI.setLibCallee(