dccp: build fixes, mdb (vfs sonode missing)

@@ -45,10 +45,12 @@
 extern int icmp_stacks_walk_step(mdb_walk_state_t *);
 extern int tcp_stacks_walk_init(mdb_walk_state_t *);
 extern int tcp_stacks_walk_step(mdb_walk_state_t *);
 extern int udp_stacks_walk_init(mdb_walk_state_t *);
 extern int udp_stacks_walk_step(mdb_walk_state_t *);
+extern int dccp_stacks_walk_init(mdb_walk_state_t *);
+extern int dccp_stacks_walk_step(mdb_walk_state_t *);
 
 extern int sonode(uintptr_t, uint_t, int, const mdb_arg_t *);
 extern int mi(uintptr_t, uint_t, int, const mdb_arg_t *);
 extern int netstat(uintptr_t, uint_t, int, const mdb_arg_t *);
 extern int dladm(uintptr_t, uint_t, int, const mdb_arg_t *);