IPVS: buffer argument to ip_vs_process_message() should not be const

It is assigned to a non-const variable and its contents are modified.
Acked-by: Hans Schillstrom <hans.schillstrom@ericsson.com>
Signed-off-by: Simon Horman <horms@verge.net.au>

net/netfilter/ipvs/ip_vs_sync.c

@@ -303,7 +303,7 @@ ip_vs_conn_fill_param_sync(int af, int protocol,
  *      Process received multicast message and create the corresponding
  *      ip_vs_conn entries.
  */
-static void ip_vs_process_message(const char *buffer, const size_t buflen)
+static void ip_vs_process_message(char *buffer, const size_t buflen)
 {
 	struct ip_vs_sync_mesg *m = (struct ip_vs_sync_mesg *)buffer;
 	struct ip_vs_sync_conn *s;