[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_sctp.c b/net/netfilter/xt_sctp.c
index b718ec6..e6e4681 100644
--- a/net/netfilter/xt_sctp.c
+++ b/net/netfilter/xt_sctp.c
@@ -46,7 +46,8 @@
 	     bool *hotdrop)
 {
 	u_int32_t chunkmapcopy[256 / sizeof (u_int32_t)];
-	sctp_chunkhdr_t _sch, *sch;
+	const sctp_chunkhdr_t *sch;
+	sctp_chunkhdr_t _sch;
 	int chunk_match_type = info->chunk_match_type;
 	const struct xt_sctp_flag_info *flag_info = info->flag_info;
 	int flag_count = info->flag_count;
@@ -121,7 +122,8 @@
         const void *matchinfo, int offset, unsigned int protoff, bool *hotdrop)
 {
 	const struct xt_sctp_info *info = matchinfo;
-	sctp_sctphdr_t _sh, *sh;
+	const sctp_sctphdr_t *sh;
+	sctp_sctphdr_t _sh;
 
 	if (offset) {
 		duprintf("Dropping non-first fragment.. FIXME\n");