lc15: led_sleep_cb: pass correct ptr to llist_move_tail

Fix compilation warning. At runtime it's not a big issue because the
"list" field is the first field of the led_list (struct
lc15bts_led_timer_list) variable. Hence, the address passed is the same.

Change-Id: Ib8bf07990800d74bfb3ad7a55eccfc65e40cd480

src/osmo-bts-litecell15/misc/lc15bts_led.c

@@ -151,7 +151,7 @@ static void led_sleep_cb(void *_data) {
 			/* Delete current timer */
 			osmo_timer_del(&led_list->led_timer.timer);
 			/* Rotate the timer list */
-			 llist_move_tail(led_list, &mgr->lc15bts_leds.list);
+			 llist_move_tail(&led_list->list, &mgr->lc15bts_leds.list);
 			break;
 		}
 	}