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/osmo-bsc_nat/bsc_nat.c b/openbsc/src/osmo-bsc_nat/bsc_nat.c
index 643b3c4..f513933 100644
--- a/openbsc/src/osmo-bsc_nat/bsc_nat.c
+++ b/openbsc/src/osmo-bsc_nat/bsc_nat.c
@@ -52,6 +52,7 @@
 
 #include <osmocom/vty/telnet_interface.h>
 #include <osmocom/vty/vty.h>
+#include <osmocom/vty/logging.h>
 
 #include <osmocom/sccp/sccp.h>
 
@@ -1286,7 +1287,7 @@
 
 	vty_info.copyright = openbsc_copyright;
 	vty_init(&vty_info);
-	logging_vty_add_cmds();
+	logging_vty_add_cmds(&log_info);
 	bsc_nat_vty_init(nat);