net: hsr: remove redundant null check

Because kfree_skb already checked NULL skb parameter,
so the additional checks are unnecessary, just remove them.
Reported-by: Hulk Robot <hulkci@huawei.com>
Signed-off-by: Wang Hai <wanghai38@huawei.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

net/hsr/hsr_forward.c

@@ -367,10 +367,8 @@ void hsr_forward_skb(struct sk_buff *skb, struct hsr_port *port)
 		port->dev->stats.tx_bytes += skb->len;
 	}
 
-	if (frame.skb_hsr)
-		kfree_skb(frame.skb_hsr);
-	if (frame.skb_std)
-		kfree_skb(frame.skb_std);
+	kfree_skb(frame.skb_hsr);
+	kfree_skb(frame.skb_std);
 	return;
 
 out_drop: