netfilter: nf_conntrack: silence warning on falling back to vmalloc()

Since 88eab472ec21 ("netfilter: conntrack: adjust nf_conntrack_buckets default
value"), the hashtable can easily hit this warning. We got reports from users
that are getting this message in a quite spamming fashion, so better silence
this.

Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
Acked-by: Florian Westphal <fw@strlen.de>

net/netfilter/nf_conntrack_core.c

@@ -1544,10 +1544,8 @@ void *nf_ct_alloc_hashtable(unsigned int *sizep, int nulls)
 	sz = nr_slots * sizeof(struct hlist_nulls_head);
 	hash = (void *)__get_free_pages(GFP_KERNEL | __GFP_NOWARN | __GFP_ZERO,
 					get_order(sz));
-	if (!hash) {
-		printk(KERN_WARNING "nf_conntrack: falling back to vmalloc.\n");
+	if (!hash)
 		hash = vzalloc(sz);
-	}
 
 	if (hash && nulls)
 		for (i = 0; i < nr_slots; i++)