x86: use sparse_memory_present_with_active_regions() on UMA

There's no need to use call memory_present() manually on UMA because
initmem_init() sets up early_node_map by calling
e820_register_active_regions().

[ Impact: cleanup ]
Signed-off-by: Pekka Enberg <penberg@cs.helsinki.fi>
LKML-Reference: <1241699742.17846.31.camel@penberg-laptop>
Signed-off-by: Ingo Molnar <mingo@elte.hu>

arch/x86/mm/init_64.c

@@ -596,11 +596,7 @@ void __init paging_init(void)
 	max_zone_pfns[ZONE_DMA32] = MAX_DMA32_PFN;
 	max_zone_pfns[ZONE_NORMAL] = max_pfn;
 
-#ifdef CONFIG_NUMA
 	sparse_memory_present_with_active_regions(MAX_NUMNODES);
-#else
-	memory_present(0, 0, max_pfn);
-#endif
 	sparse_init();
 	free_area_init_nodes(max_zone_pfns);
 }