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/transport_mbox.c b/transport_mbox.c
index dd412a4..5db978f 100644
--- a/transport_mbox.c
+++ b/transport_mbox.c
@@ -635,7 +635,7 @@
 	return __transport_mbox_init(context, MBOX_HOST_PATH);
 }
 
-void free_mbox_dev(struct mbox_context *context)
+void transport_mbox_free(struct mbox_context *context)
 {
 	close(context->fds[MBOX_FD].fd);
 }