connector/dm: Fixed a compilation warning

Signed-off-by: NPhilipp Reisner <philipp.reisner@linbit.com>
Acked-by: NLars Ellenberg <lars.ellenberg@linbit.com>
Acked-by: NEvgeniy Polyakov <zbr@ioremap.net>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

drivers/md/dm-log-userspace-transfer.c

@@ -129,9 +129,8 @@ static int fill_pkg(struct cn_msg *msg, struct dm_ulog_request *tfr)
  * This is the connector callback that delivers data
  * that was sent from userspace.
  */
-static void cn_ulog_callback(void *data, struct netlink_skb_parms *nsp)
+static void cn_ulog_callback(struct cn_msg *msg, struct netlink_skb_parms *nsp)
 {
-	struct cn_msg *msg = (struct cn_msg *)data;
 	struct dm_ulog_request *tfr = (struct dm_ulog_request *)(msg + 1);
 
 	spin_lock(&receiving_list_lock);