netfilter: xt_HMARK: potential NULL dereference in get_inner_hdr()

There is a typo in the error checking and "&&" was used instead of "||".
If skb_header_pointer() returns NULL then it leads to a NULL
dereference.
Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
Acked-by: Hans Schillstrom <hans.schillstrom@ericsson.com>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

net/netfilter/xt_HMARK.c

@@ -223,7 +223,7 @@ static int get_inner_hdr(const struct sk_buff *skb, int iphsz, int *nhoff)
 
 	/* Not enough header? */
 	icmph = skb_header_pointer(skb, *nhoff + iphsz, sizeof(_ih), &_ih);
-	if (icmph == NULL && icmph->type > NR_ICMP_TYPES)
+	if (icmph == NULL || icmph->type > NR_ICMP_TYPES)
 		return 0;
 
 	/* Error message? */