tbf: Use LListHead instead of llist_pods

LListHead does basically the same like llist_pods, but more C++ish
and with type safety.

This commit turns the former list field of gprs_rlcmac_tbf into a
private field, provides accessors, moves the related code from
pcu_vty.c to pcu_vty_functions.cpp, and removes the llist_pods
type and related code.

Sponsored-by: On-Waves ehf
diff --git a/src/pcu_vty_functions.h b/src/pcu_vty_functions.h
index 170ad2e..35acf64 100644
--- a/src/pcu_vty_functions.h
+++ b/src/pcu_vty_functions.h
@@ -28,14 +28,13 @@
 struct gprs_rlcmac_bts;
 
 int pcu_vty_config_write_pcu_ext(struct vty *vty);
+int pcu_vty_show_tbf_all(struct vty *vty, struct gprs_rlcmac_bts *bts_data);
 int pcu_vty_show_ms_all(struct vty *vty, struct gprs_rlcmac_bts *bts_data);
 int pcu_vty_show_ms_by_tlli(struct vty *vty, struct gprs_rlcmac_bts *bts_data,
 	uint32_t tlli);
 int pcu_vty_show_ms_by_imsi(struct vty *vty, struct gprs_rlcmac_bts *bts_data,
 	const char *imsi);
 
-void tbf_print_vty_info(struct vty *vty, struct llist_head *tbf);
-
 #ifdef __cplusplus
 }
 #endif