[NETFILTER]: Replace sk_buff ** with sk_buff *

With all the users of the double pointers removed, this patch mops up by
finally replacing all occurances of sk_buff ** in the netfilter API by
sk_buff *.

Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/net/ipv4/netfilter/nf_nat_tftp.c b/net/ipv4/netfilter/nf_nat_tftp.c
index 04dfeae..0ecec70 100644
--- a/net/ipv4/netfilter/nf_nat_tftp.c
+++ b/net/ipv4/netfilter/nf_nat_tftp.c
@@ -20,7 +20,7 @@
 MODULE_LICENSE("GPL");
 MODULE_ALIAS("ip_nat_tftp");
 
-static unsigned int help(struct sk_buff **pskb,
+static unsigned int help(struct sk_buff *skb,
 			 enum ip_conntrack_info ctinfo,
 			 struct nf_conntrack_expect *exp)
 {