ppp: remove some pointless conditionals before kfree_skb()

Remove some pointless conditionals before kfree_skb().

Signed-off-by: Wei Yongjun <yjwei@cn.fujitsu.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/drivers/net/ppp_synctty.c b/drivers/net/ppp_synctty.c
index 1e892b7..3ea791d16 100644
--- a/drivers/net/ppp_synctty.c
+++ b/drivers/net/ppp_synctty.c
@@ -281,8 +281,7 @@
 
 	ppp_unregister_channel(&ap->chan);
 	skb_queue_purge(&ap->rqueue);
-	if (ap->tpkt)
-		kfree_skb(ap->tpkt);
+	kfree_skb(ap->tpkt);
 	kfree(ap);
 }