[netif] remove unused mNext pointer (#4520)
diff --git a/src/core/net/netif.cpp b/src/core/net/netif.cpp
index 3108339..0d69905 100644
--- a/src/core/net/netif.cpp
+++ b/src/core/net/netif.cpp
@@ -85,7 +85,6 @@
     , mUnicastAddresses()
     , mMulticastAddresses()
     , mMulticastPromiscuous(false)
-    , mNext(NULL)
     , mAddressCallback(NULL)
     , mAddressCallbackContext(NULL)
 {
diff --git a/src/core/net/netif.hpp b/src/core/net/netif.hpp
index e40bb31..853ab55 100644
--- a/src/core/net/netif.hpp
+++ b/src/core/net/netif.hpp
@@ -404,7 +404,6 @@
     LinkedList<NetifUnicastAddress>   mUnicastAddresses;
     LinkedList<NetifMulticastAddress> mMulticastAddresses;
     bool                              mMulticastPromiscuous;
-    Netif *                           mNext;
 
     otIp6AddressCallback mAddressCallback;
     void *               mAddressCallbackContext;