Remove undefined param passed to {logging,osmo_stats}_vty_add_cmds

Since March 15th 2017, libosmocore API logging_vty_add_cmds() had its
parameter removed (c65c5b4ea075ef6cef11fff9442ae0b15c1d6af7). However,
definition in C file doesn't contain "(void)", which means number of
parameters is undefined and thus compiler doesn't complain. Let's remove
parameters from all callers before enforcing "(void)" on it.

Change-Id: I31a286bebe3229671d9960ae32a753d260a26b1d
Related: OS#4138
diff --git a/src/hnbgw.c b/src/hnbgw.c
index fa655ae..3f94a01 100644
--- a/src/hnbgw.c
+++ b/src/hnbgw.c
@@ -539,7 +539,7 @@
 	osmo_ss7_vty_init_asp(tall_hnb_ctx);
 	osmo_sccp_vty_init();
 	hnbgw_vty_init(g_hnb_gw, tall_hnb_ctx);
-	logging_vty_add_cmds(&hnbgw_log_info);
+	logging_vty_add_cmds();
 
 	/* Handle options after vty_init(), for --version */
 	handle_options(argc, argv);