nat/vty: Do not print token update statement

On start this would print one line per BSC and this doesn't add
a lot of value. Let's just remove this logging message.
diff --git a/openbsc/src/osmo-bsc_nat/bsc_nat_vty.c b/openbsc/src/osmo-bsc_nat/bsc_nat_vty.c
index 55f3dbf..3708bc2 100644
--- a/openbsc/src/osmo-bsc_nat/bsc_nat_vty.c
+++ b/openbsc/src/osmo-bsc_nat/bsc_nat_vty.c
@@ -881,11 +881,8 @@
 {
 	struct bsc_config *conf = vty->index;
 
-	if (strncmp(conf->token, argv[0], 128) != 0) {
-		vty_out(vty, "updated token: %s -> %s%s", conf->token, argv[0],
-			VTY_NEWLINE);
+	if (strncmp(conf->token, argv[0], 128) != 0)
 		conf->token_updated = true;
-	}
 
 	bsc_replace_string(conf, &conf->token, argv[0]);
 	return CMD_SUCCESS;