netfilter: fix hardcoded size assumptions

get_random_bytes() is sometimes called with a hard coded size assumption
of an integer. This could not be true for next centuries. This patch
replace it with a compile time statement.

Signed-off-by: Hagen Paul Pfeifer <hagen@jauu.net>
Signed-off-by: Patrick McHardy <kaber@trash.net>
diff --git a/net/netfilter/xt_hashlimit.c b/net/netfilter/xt_hashlimit.c
index f97fded..2482055 100644
--- a/net/netfilter/xt_hashlimit.c
+++ b/net/netfilter/xt_hashlimit.c
@@ -149,7 +149,7 @@
 	/* initialize hash with random val at the time we allocate
 	 * the first hashtable entry */
 	if (!ht->rnd_initialized) {
-		get_random_bytes(&ht->rnd, 4);
+		get_random_bytes(&ht->rnd, sizeof(ht->rnd));
 		ht->rnd_initialized = 1;
 	}