Fix slab build failure if !CONFIG_ZONE_DMA

I also needed this to get 2.6.20-rc6-mm2 to build. Fixes the fix of the
complainer about the fixes.

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

Index: linux-2.6.20-rc6-mm2/mm/slab.c
===================================================================
--- linux-2.6.20-rc6-mm2.orig/mm/slab.c	2007-01-30 13:56:10.683074081 -0600
+++ linux-2.6.20-rc6-mm2/mm/slab.c	2007-01-30 13:57:13.152420752 -0600
@@ -1504,14 +1504,15 @@ void __init kmem_cache_init(void)
 					ARCH_KMALLOC_FLAGS|SLAB_PANIC,
 					NULL, NULL);
 		}
-		if (CONFIG_ZONE_DMA_FLAG)
-			sizes->cs_dmacachep = kmem_cache_create(
+#ifdef CONFIG_ZONE_DMA
+		sizes->cs_dmacachep = kmem_cache_create(
 					names->name_dma,
 					sizes->cs_size,
 					ARCH_KMALLOC_MINALIGN,
 					ARCH_KMALLOC_FLAGS|SLAB_CACHE_DMA|
 						SLAB_PANIC,
 					NULL, NULL);
+#endif
 		sizes++;
 		names++;
 	}