em28xx_unregister_extension
em28xx_unregister_extension(&audio_ops);
EXPORT_SYMBOL(em28xx_unregister_extension);
em28xx_unregister_extension(&dvb_ops);
em28xx_unregister_extension(&rc_ops);
em28xx_unregister_extension(&v4l2_ops);
void em28xx_unregister_extension(struct em28xx_ops *dev);