bsc: change bsc_vty_init to take logging categories as parameter

This change is required to finish the integration of the VTY and
the per-application logging categories that provides:

"vty: integration with logging framework"

in libosmocore.

It has been tested with osmo-nitb. The other just compiled tested.
diff --git a/openbsc/src/libbsc/bsc_vty.c b/openbsc/src/libbsc/bsc_vty.c
index 1afaed3..d74543d 100644
--- a/openbsc/src/libbsc/bsc_vty.c
+++ b/openbsc/src/libbsc/bsc_vty.c
@@ -2650,7 +2650,7 @@
 extern int bsc_vty_init_extra(void);
 extern const char *openbsc_copyright;
 
-int bsc_vty_init(void)
+int bsc_vty_init(const struct log_info *cat)
 {
 	install_element_ve(&show_net_cmd);
 	install_element_ve(&show_bts_cmd);
@@ -2666,7 +2666,7 @@
 
 	install_element_ve(&show_paging_cmd);
 
-	logging_vty_add_cmds();
+	logging_vty_add_cmds(cat);
 	install_element(CFG_LOG_NODE, &logging_fltr_imsi_cmd);
 
 	install_element(CONFIG_NODE, &cfg_net_cmd);