chelsio/chtls: fix always leaking ctrl_skb

Correct skb refcount in alloc_ctrl_skb(), causing skb memleak
when chtls_send_abort() called with NULL skb.
it was always leaking the skb, correct it by incrementing skb
refs by one.

Fixes: cc35c88 ("crypto : chtls - CPL handler definition")
Signed-off-by: Vinay Kumar Yadav <vinay.yadav@chelsio.com>
Link: https://lore.kernel.org/r/20201102173909.24826-1-vinay.yadav@chelsio.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

drivers/net/ethernet/chelsio/inline_crypto/chtls/chtls_cm.c

@@ -212,7 +212,7 @@ static struct sk_buff *alloc_ctrl_skb(struct sk_buff *skb, int len)
 {
 	if (likely(skb && !skb_shared(skb) && !skb_cloned(skb))) {
 		__skb_trim(skb, 0);
-		refcount_add(2, &skb->users);
+		refcount_inc(&skb->users);
 	} else {
 		skb = alloc_skb(len, GFP_KERNEL | __GFP_NOFAIL);
 	}