transport: mbox: Rename free_mbox_dev to transport_mbox_free

Change-Id: Ie400ccfada8890ddc626deadabd58fe4bf4c3cd3
Signed-off-by: Andrew Jeffery <andrew@aj.id.au>
diff --git a/mboxd.c b/mboxd.c
index ecf0caf..a9ef8d9 100644
--- a/mboxd.c
+++ b/mboxd.c
@@ -414,7 +414,7 @@
 	dbus_free(context);
 	flash_dev_free(context);
 	lpc_dev_free(context);
-	free_mbox_dev(context);
+	transport_mbox_free(context);
 	windows_free(context);
 	protocol_free(context);
 	free(context);