Make classof in MemSDNode consistent with MemIntrinsicSDNode

If INTRINSIC_W_CHAIN and INTRINSIC_VOID are MemIntrinsicSDNodes, and a
MemIntrinsicSDNode is a MemSDNode, then INTRINSIC_W_CHAIN and INTRINSIC_VOID
must be MemSDNodes too.

Noticed by inspection.

llvm-svn: 214452

include/llvm/CodeGen/SelectionDAGNodes.h

@@ -1158,6 +1158,8 @@ public:
            N->getOpcode() == ISD::ATOMIC_LOAD_UMAX    ||
            N->getOpcode() == ISD::ATOMIC_LOAD         ||
            N->getOpcode() == ISD::ATOMIC_STORE        ||
+           N->getOpcode() == ISD::INTRINSIC_W_CHAIN   ||
+           N->getOpcode() == ISD::INTRINSIC_VOID      ||
            N->isTargetMemoryOpcode();
   }
 };