zoned VM stats: nr_slab is accurate, fix comment

nr_slab is accurate with the zoned VM stats. Remove the comment
that states otherwise in swap_prefetch.c

Signed-off-by: Christoph Lameter <clameter@sgi.com>

Index: linux-2.6.17-rc6-mm1/mm/swap_prefetch.c
===================================================================
--- linux-2.6.17-rc6-mm1.orig/mm/swap_prefetch.c	2006-06-09 10:30:52.363683655 -0700
+++ linux-2.6.17-rc6-mm1/mm/swap_prefetch.c	2006-06-09 11:17:22.126406920 -0700
@@ -386,10 +386,6 @@ static int prefetch_suitable(void)
 		/*
 		 * >2/3 of the ram on this node is mapped, slab, swapcache or
 		 * dirty, we need to leave some free for pagecache.
-		 * Note that currently nr_slab is innacurate on numa because
-		 * nr_slab is incremented on the node doing the accounting
-		 * even if the slab is being allocated on a remote node. This
-		 * would be expensive to fix and not of great significance.
 		 */
 		limit = global_page_state(NR_MAPPED) +
 			global_page_state(NR_SLAB) +