greybus: camera-gb: Extend gb camera module structure

Add additional information in gb camera module.
 - interface ID
 - reference count
 - release handle
Signed-off-by: NEvgeniy Borisov <eborisov@mm-sol.com>
Reviewed-by: NGjorgji Rosikopulos <grosikopulos@mm-sol.com>
Reviewed-by: NLaurent Pinchart <laurent.pinchart@linaro.org>
Signed-off-by: NGreg Kroah-Hartman <gregkh@google.com>

drivers/staging/greybus/gb-camera.h

@@ -105,12 +105,18 @@ struct gb_camera_ops {
  * struct gb_camera_module - Represents greybus camera module.
  * @priv: Module private data, passed to all camera operations.
  * @ops: Greybus camera operation callbacks.
+ * @interface_id: Interface id of the module.
+ * @refcount: Reference counting object.
+ * @release: Module release function.
  * @list: List entry in the camera modules list.
  */
 struct gb_camera_module {
 	void *priv;
 	const struct gb_camera_ops *ops;
 
+	unsigned int interface_id;
+	struct kref refcount;
+	void (*release)(struct kref *kref);
 	struct list_head list; /* Global list */
 };