appletalk: fix a coccinella warning in net/appletalk/ddp.c

This warning is introduced by commit 7b30600c ("appletalk:
fix checkpatch error with indent"), So fix it.
Signed-off-by: NWang Weidong <wangweidong1@huawei.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

net/appletalk/ddp.c

@@ -1808,7 +1808,7 @@ static int atalk_ioctl(struct socket *sock, unsigned int cmd, unsigned long arg)
 		long amount = 0;
 
 		if (skb)
-		amount = skb->len - sizeof(struct ddpehdr);
+			amount = skb->len - sizeof(struct ddpehdr);
 		rc = put_user(amount, (int __user *)argp);
 		break;
 	}