s390/ctcm: Delete unnecessary checks before the macro call “dev_kfree_skb”

The dev_kfree_skb() function performs also input parameter validation.
Thus the test around the shown calls is not needed.

This issue was detected by using the Coccinelle software.
Signed-off-by: Markus Elfring <elfring@users.sourceforge.net>
Signed-off-by: Julian Wiedmann <jwi@linux.ibm.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

drivers/s390/net/ctcm_main.c

@@ -1072,10 +1072,8 @@ static void ctcm_free_netdevice(struct net_device *dev)
 		if (grp) {
 			if (grp->fsm)
 				kfree_fsm(grp->fsm);
-			if (grp->xid_skb)
-				dev_kfree_skb(grp->xid_skb);
-			if (grp->rcvd_xid_skb)
-				dev_kfree_skb(grp->rcvd_xid_skb);
+			dev_kfree_skb(grp->xid_skb);
+			dev_kfree_skb(grp->rcvd_xid_skb);
 			tasklet_kill(&grp->mpc_tasklet2);
 			kfree(grp);
 			priv->mpcg = NULL;