utils: fix in/pipe utilities

These examples stopped building with 3b36d17cf.

Fixes: 3b36d17cf18bd9ad13f043256371222e2845e4d9
Change-Id: I14218769afd1e9b8171de33b88028ef4a052ce17
Signed-off-by: Brad Bishop <bradleyb@fuzziesquirrel.com>
diff --git a/utils/mctp-in.c b/utils/mctp-in.c
index ce06bb4..43d96ec 100644
--- a/utils/mctp-in.c
+++ b/utils/mctp-in.c
@@ -32,7 +32,7 @@
 
 	mctp_serial_open_fd(serial, STDIN_FILENO);
 
-	mctp_serial_register_bus(serial, mctp, 8);
+	mctp_register_bus(mctp, mctp_binding_serial_core(serial), 8);
 
 	mctp_set_rx_all(mctp, rx_message, NULL);