gprs_ns2: always use the same method to print NSVCs

The binds also print a list of associated NSVC when
dumping the bind.
However the binds using their own representation of
printing the NSVC which is different to `show ns entities`.
Use the same function to print NS-VC.

Before:
  NSVCI 00000: udp)[127.0.0.1]:23000<>[127.0.0.1]:22000
After:
  NSVCI none: UNCONFIGURED DYNAMIC data_weight=1 sig_weight=1 udp)[127.0.0.1]:23000<>[127.0.0.1]:22000

Change-Id: If31ec6c1c07dc134ab1ddeb915bc89747c7be048
diff --git a/src/gb/gprs_ns2_internal.h b/src/gb/gprs_ns2_internal.h
index df51ff5..6cfef44 100644
--- a/src/gb/gprs_ns2_internal.h
+++ b/src/gb/gprs_ns2_internal.h
@@ -396,6 +396,7 @@
 int ns2_vc_is_unblocked(struct gprs_ns2_vc *nsvc);
 int ns2_vc_block(struct gprs_ns2_vc *nsvc);
 int ns2_vc_unblock(struct gprs_ns2_vc *nsvc);
+void ns2_vty_dump_nsvc(struct vty *vty, struct gprs_ns2_vc *nsvc, bool stats);
 
 /* nse */
 void ns2_nse_notify_unblocked(struct gprs_ns2_vc *nsvc, bool unblocked);