[mle] add missing defs when LONG_ROUTES is enabled (#5858)

src/core/thread/mle_router.cpp

@@ -4026,11 +4026,11 @@ void MleRouter::FillRouteTlv(RouteTlv &aTlv, Neighbor *aNeighbor)
 
         routerCount = mRouterTable.GetActiveRouterCount();
 
-        if (routerCount > RouteTlv::kLinkAcceptMaxRouters)
+        if (routerCount > kLinkAcceptMaxRouters)
         {
             for (uint8_t routerId = 0; routerId <= kMaxRouterId; routerId++)
             {
-                if (routerCount <= RouteTlv::kLinkAcceptMaxRouters)
+                if (routerCount <= kLinkAcceptMaxRouters)
                 {
                     break;
                 }
@@ -4053,7 +4053,7 @@ void MleRouter::FillRouteTlv(RouteTlv &aTlv, Neighbor *aNeighbor)
 
             // Ensure that the neighbor will process the current
             // Route64 TLV in a subsequent message exchange
-            routerIdSequence -= RouteTlv::kLinkAcceptSequenceRollback;
+            routerIdSequence -= kLinkAcceptSequenceRollback;
         }
     }
 

src/core/thread/mle_tlvs.hpp

@@ -239,16 +239,6 @@ OT_TOOL_PACKED_BEGIN
 class RouteTlv : public Tlv, public TlvInfo<Tlv::kRoute>
 {
 public:
-    enum
-    {
-#if OPENTHREAD_CONFIG_TIME_SYNC_ENABLE
-        kLinkAcceptMaxRouters = 3,
-#else
-        kLinkAcceptMaxRouters = 20,
-#endif
-        kLinkAcceptSequenceRollback = 64,
-    };
-
     /**
      * This method initializes the TLV.
      *

src/core/thread/mle_types.hpp

@@ -106,6 +106,13 @@ enum
                           1000, ///< Minimum timeout(in seconds) for data poll
     kMinTimeout = (kMinTimeoutKeepAlive >= kMinTimeoutDataPoll ? kMinTimeoutKeepAlive
                                                                : kMinTimeoutDataPoll), ///< Minimum timeout(in seconds)
+
+#if OPENTHREAD_CONFIG_TIME_SYNC_ENABLE
+    kLinkAcceptMaxRouters = 3, ///< Maximum Route TLV entries in a Link Accept message.
+#else
+    kLinkAcceptMaxRouters = 20, ///< Maximum Route TLV entries in a Link Accept message.
+#endif
+    kLinkAcceptSequenceRollback = 64, ///< Route Sequence value rollback in a Link Accept message.
 };
 
 enum