[NETFILTER]: annotate xtables targets with const and remove casts

Signed-off-by: Jan Engelhardt <jengelh@computergmbh.de>
Signed-off-by: Patrick McHardy <kaber@trash.net>
diff --git a/net/netfilter/xt_tcpudp.c b/net/netfilter/xt_tcpudp.c
index 4fa3b66..951b06b 100644
--- a/net/netfilter/xt_tcpudp.c
+++ b/net/netfilter/xt_tcpudp.c
@@ -42,7 +42,8 @@
 		bool *hotdrop)
 {
 	/* tcp.doff is only 4 bits, ie. max 15 * 4 bytes */
-	u_int8_t _opt[60 - sizeof(struct tcphdr)], *op;
+	const u_int8_t *op;
+	u_int8_t _opt[60 - sizeof(struct tcphdr)];
 	unsigned int i;
 
 	duprintf("tcp_match: finding option\n");
@@ -72,7 +73,8 @@
        const struct net_device *out, const struct xt_match *match,
        const void *matchinfo, int offset, unsigned int protoff, bool *hotdrop)
 {
-	struct tcphdr _tcph, *th;
+	const struct tcphdr *th;
+	struct tcphdr _tcph;
 	const struct xt_tcp *tcpinfo = matchinfo;
 
 	if (offset) {
@@ -144,7 +146,8 @@
        const struct net_device *out, const struct xt_match *match,
        const void *matchinfo, int offset, unsigned int protoff, bool *hotdrop)
 {
-	struct udphdr _udph, *uh;
+	const struct udphdr *uh;
+	struct udphdr _udph;
 	const struct xt_udp *udpinfo = matchinfo;
 
 	/* Must not be a fragment. */