nbr-table: fix default value for NBR_TABLE_MAX_NEIGHBORS
#ifdef NBR_TABLE_CONF_MAX_NEIGHBORS
#define NBR_TABLE_MAX_NEIGHBORS NBR_TABLE_CONF_MAX_NEIGHBORS
#else /* NBR_TABLE_CONF_MAX_NEIGHBORS */
-#define NBR_TABLE_MAX_NEIGHBORS NBR_TABLE_CONF_MAX_NEIGHBORS
+#define NBR_TABLE_MAX_NEIGHBORS 8
#endif /* NBR_TABLE_CONF_MAX_NEIGHBORS */
/* An item in a neighbor table */
