[AArch64] Remove unnecessary DL variable. NFC

Author: davemgreen

llvm/lib/Target/AArch64/AArch64TargetTransformInfo.cpp

@@ -6369,7 +6369,6 @@ bool AArch64TTIImpl::isProfitableToSinkOperands(
         // the backend to generate a umull.
         unsigned Bitwidth = I->getType()->getScalarSizeInBits();
         APInt UpperMask = APInt::getHighBitsSet(Bitwidth, Bitwidth / 2);
-        const DataLayout &DL = I->getDataLayout();
         if (!MaskedValueIsZero(OperandInstr, UpperMask, DL))
           continue;
         NumZExts++;