greybus: remove unused host-device id

Remove unused device_id field from host-device structure.
Signed-off-by: Johan Hovold <johan@hovoldconsulting.com>
Reviewed-by: Viresh Kumar <viresh.kumar@linaro.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@google.com>

drivers/staging/greybus/greybus.h

@@ -93,7 +93,6 @@ struct greybus_host_device {
 	struct list_head interfaces;
 	struct list_head connections;
 	struct ida cport_id_map;
-	u8 device_id;
 
 	/* Number of CPorts supported by the UniPro IP */
 	size_t num_cports;