[AArch64] remove bogus comment; NFC

I added this comment with D42323, but as discussed in D42806, the architecture
does the right thing for denorms. We don't even need the select on 0.0 here?

llvm-svn: 323996

llvm/lib/Target/AArch64/AArch64ISelLowering.cpp

@@ -5007,9 +5007,6 @@ SDValue AArch64TargetLowering::getSqrtEstimate(SDValue Operand,
         Step = DAG.getNode(AArch64ISD::FRSQRTS, DL, VT, Operand, Step, Flags);
         Estimate = DAG.getNode(ISD::FMUL, DL, VT, Estimate, Step, Flags);
       }
-      // FIXME: This does not detect denorm inputs, so we might produce INF
-      // when we should produce 0.0. Try to refactor the code in DAGCombiner,
-      // so we don't have to duplicate it here.
       if (!Reciprocal) {
         EVT CCVT = getSetCCResultType(DAG.getDataLayout(), *DAG.getContext(),
                                       VT);