[NETFILTER]: Fix offset calculation in amanda conntrack helper

Signed-off-by: Patrick McHardy <kaber@trash.net>
Signed-off-by: Harald Welte <laforge@netfilter.org>
Signed-off-by: David S. Miller <davem@redhat.com>

net/ipv4/netfilter/ip_conntrack_amanda.c

@@ -107,7 +107,7 @@ static int help(struct sk_buff *skb,
 		exp->mask.dst.u.tcp.port = 0xFFFF;
 
 		exp_amanda_info = &exp->help.exp_amanda_info;
-		exp_amanda_info->offset = data - amanda_buffer;
+		exp_amanda_info->offset = tmp - amanda_buffer;
 		exp_amanda_info->port   = port;
 		exp_amanda_info->len    = len;