vty: remove ignored logging parameters

Since ce9fec3e896571835ac5bfd2980d6836f2b29f0d libosmocore ignores
parameters to log_vty_command_* functions. Hence parameter of
logging_vty_add_cmds() is ignored too. As we depend on much later
libosmocore version anyway, we can simplify code somewhat by removing
parameters which will be ignored anyway.

Change-Id: I62f752fd88f1d8fefa563648f9864c7c31f87991
diff --git a/openbsc/src/osmo-bsc_nat/bsc_nat_vty.c b/openbsc/src/osmo-bsc_nat/bsc_nat_vty.c
index 706e507..deb98fc 100644
--- a/openbsc/src/osmo-bsc_nat/bsc_nat_vty.c
+++ b/openbsc/src/osmo-bsc_nat/bsc_nat_vty.c
@@ -1329,8 +1329,8 @@
 
 
 /* called by the telnet interface... we have our own init above */
-int bsc_vty_init(const struct log_info *cat, struct gsm_network *network)
+int bsc_vty_init(struct gsm_network *network)
 {
-	logging_vty_add_cmds(cat);
+	logging_vty_add_cmds(NULL);
 	return 0;
 }