[patch] fix hugepage unuseable issu on non-NUMA machine

["alex.shi" <alex.shi@intel.com>]

73d60b7f747176dbdff826c4127d22e1fd3f9f74 commit introduced a nodes_clear
function for NUMA machine. But seems the commit omits non-NUMA machine.
If find_zone_movable_pfns_for_nodes/early_calculate_totalpages has no
chance to run. nodes_clear will block HUPEPAGE using in my specjbb2005
testing. 


So maybe we need to disable nodes_clear sometimes. With the following
patch. specjbb2005 recovered. 


Signed-off-by: Alex Shi <alex.shi@intel.com>
---
diff --git a/mm/page_alloc.c b/mm/page_alloc.c
index 5d714f8..46ff861 100644
--- a/mm/page_alloc.c
+++ b/mm/page_alloc.c
@@ -4246,7 +4246,8 @@ void __init free_area_init_nodes(unsigned long *max_zone_pfn)
 	 * find_zone_movable_pfns_for_nodes/early_calculate_totalpages init
 	 * that node_mask, clear it at first
 	 */
-	nodes_clear(node_states[N_HIGH_MEMORY]);
+	if (required_kernelcore)
+		nodes_clear(node_states[N_HIGH_MEMORY]);
 	/* Initialise every node */
 	mminit_verify_pageflags_layout();
 	setup_nr_node_ids();