mctp: remove unnecessary check before calling kfree_skb()

The skb will be checked inside kfree_skb(), so remove the
outside check.
Signed-off-by: Yang Yingliang <yangyingliang@huawei.com>
Link: https://lore.kernel.org/r/20211130031243.768823-1-yangyingliang@huawei.comSigned-off-by: Jakub Kicinski <kuba@kernel.org>

net/mctp/af_mctp.c

@@ -405,8 +405,7 @@ static void mctp_sk_unhash(struct sock *sk)
 		trace_mctp_key_release(key, MCTP_TRACE_KEY_CLOSED);
 
 		spin_lock(&key->lock);
-		if (key->reasm_head)
-			kfree_skb(key->reasm_head);
+		kfree_skb(key->reasm_head);
 		key->reasm_head = NULL;
 		key->reasm_dead = true;
 		key->valid = false;

net/mctp/route.c

@@ -231,9 +231,7 @@ static void __mctp_key_unlock_drop(struct mctp_sk_key *key, struct net *net,
 	/* and one for the local reference */
 	mctp_key_unref(key);
 
-	if (skb)
-		kfree_skb(skb);
-
+	kfree_skb(skb);
 }
 
 #ifdef CONFIG_MCTP_FLOWS