greybus: core: clean up ida memory for host controller

We forgot to free any ida internal structures that were used by this
host controller structure when we free the memory for the controller.
So fix that up by doing so in the release function.
Signed-off-by: Greg Kroah-Hartman <gregkh@google.com>
Reviewed-by: Viresh Kumar <viresh.kumar@linaro.org>

drivers/staging/greybus/core.c

@@ -161,6 +161,7 @@ static void free_hd(struct kref *kref)
 
 	hd = container_of(kref, struct greybus_host_device, kref);
 
+	ida_destroy(&hd->cport_id_map);
 	kfree(hd);
 	mutex_unlock(&hd_mutex);
 }