esp: Fix misplaced spin_unlock_bh.

A recent commit moved esp_alloc_tmp() out of a lock
protected region, but forgot to remove the unlock from
the error path. This patch removes the forgotten unlock.
While at it, remove some unneeded error assignments too.

Fixes: fca11ebde3f0 ("esp4: Reorganize esp_output")
Fixes: 383d0350f2cc ("esp6: Reorganize esp_output")
Reported-by: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: Steffen Klassert <steffen.klassert@secunet.com>

net/ipv4/esp4.c

@@ -356,11 +356,8 @@ int esp_output_tail(struct xfrm_state *x, struct sk_buff *skb, struct esp_info *
 	ivlen = crypto_aead_ivsize(aead);
 
 	tmp = esp_alloc_tmp(aead, esp->nfrags + 2, extralen);
-	if (!tmp) {
-		spin_unlock_bh(&x->lock);
-		err = -ENOMEM;
+	if (!tmp)
 		goto error;
-	}
 
 	extra = esp_tmp_extra(tmp);
 	iv = esp_tmp_iv(aead, tmp, extralen);
@@ -389,7 +386,6 @@ int esp_output_tail(struct xfrm_state *x, struct sk_buff *skb, struct esp_info *
 		spin_lock_bh(&x->lock);
 		if (unlikely(!skb_page_frag_refill(allocsize, pfrag, GFP_ATOMIC))) {
 			spin_unlock_bh(&x->lock);
-			err = -ENOMEM;
 			goto error;
 		}
 

net/ipv6/esp6.c

@@ -330,11 +330,8 @@ int esp6_output_tail(struct xfrm_state *x, struct sk_buff *skb, struct esp_info
 	ivlen = crypto_aead_ivsize(aead);
 
 	tmp = esp_alloc_tmp(aead, esp->nfrags + 2, seqhilen);
-	if (!tmp) {
-		spin_unlock_bh(&x->lock);
-		err = -ENOMEM;
+	if (!tmp)
 		goto error;
-	}
 
 	seqhi = esp_tmp_seqhi(tmp);
 	iv = esp_tmp_iv(aead, tmp, seqhilen);
@@ -362,7 +359,6 @@ int esp6_output_tail(struct xfrm_state *x, struct sk_buff *skb, struct esp_info
 		spin_lock_bh(&x->lock);
 		if (unlikely(!skb_page_frag_refill(allocsize, pfrag, GFP_ATOMIC))) {
 			spin_unlock_bh(&x->lock);
-			err = -ENOMEM;
 			goto error;
 		}