ipv6: Remove some pointless conditionals before kfree_skb()

Remove some pointless conditionals before kfree_skb().

The semantic match that finds the problem is as follows:
(http://www.emn.fr/x-info/coccinelle/)

// <smpl>
@@
expression E;
@@
- if (E)
- 	kfree_skb(E);
+ kfree_skb(E);
// </smpl>

Signed-off-by: Wei Yongjun <yjwei@cn.fujitsu.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/net/ipv6/tcp_ipv6.c b/net/ipv6/tcp_ipv6.c
index 00f1269..4b5aa18 100644
--- a/net/ipv6/tcp_ipv6.c
+++ b/net/ipv6/tcp_ipv6.c
@@ -533,8 +533,7 @@
 
 static void tcp_v6_reqsk_destructor(struct request_sock *req)
 {
-	if (inet6_rsk(req)->pktopts)
-		kfree_skb(inet6_rsk(req)->pktopts);
+	kfree_skb(inet6_rsk(req)->pktopts);
 }
 
 #ifdef CONFIG_TCP_MD5SIG
@@ -1611,8 +1610,7 @@
 		}
 	}
 
-	if (opt_skb)
-		kfree_skb(opt_skb);
+	kfree_skb(opt_skb);
 	return 0;
 }