esp6: remove redundant variable err

Variable err is being assigned a value that is not read, the assignment
is redundant and so is the variable. Remove it.

Cleans up clang scan warning:
net/ipv6/esp6_offload.c:64:7: warning: Although the value stored to 'err'
is used in the enclosing expression, the value is never actually read
from 'err' [deadcode.DeadStores]
Signed-off-by: NColin Ian King <colin.i.king@gmail.com>
Signed-off-by: NSteffen Klassert <steffen.klassert@secunet.com>

net/ipv6/esp6_offload.c

@@ -56,12 +56,11 @@ static struct sk_buff *esp6_gro_receive(struct list_head *head,
 	__be32 seq;
 	__be32 spi;
 	int nhoff;
-	int err;
 
 	if (!pskb_pull(skb, offset))
 		return NULL;
 
-	if ((err = xfrm_parse_spi(skb, IPPROTO_ESP, &spi, &seq)) != 0)
+	if (xfrm_parse_spi(skb, IPPROTO_ESP, &spi, &seq) != 0)
 		goto out;
 
 	xo = xfrm_offload(skb);