x86-64, NUMA: Kill mem_nodes_parsed

With all memory configuration information now carried in numa_meminfo,
there's no need to keep mem_nodes_parsed separate.  Drop it and use
numa_nodes_parsed for CPU / memory-less nodes.

A new helper numa_nodemask_from_meminfo() is added to calculate
memnode mask on the fly which is currently used to set
node_possible_map.

This simplifies NUMA init methods a bit and removes a source of
possible inconsistencies.

Signed-off-by: Tejun Heo <tj@kernel.org>
Cc: Yinghai Lu <yinghai@kernel.org>
Cc: Brian Gerst <brgerst@gmail.com>
Cc: Cyrill Gorcunov <gorcunov@gmail.com>
Cc: Shaohui Zheng <shaohui.zheng@intel.com>
Cc: David Rientjes <rientjes@google.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: H. Peter Anvin <hpa@linux.intel.com>
diff --git a/arch/x86/mm/amdtopology_64.c b/arch/x86/mm/amdtopology_64.c
index e76bffa..fd7b609 100644
--- a/arch/x86/mm/amdtopology_64.c
+++ b/arch/x86/mm/amdtopology_64.c
@@ -122,7 +122,7 @@
 			       nodeid, (base >> 8) & 3, (limit >> 8) & 3);
 			return -EINVAL;
 		}
-		if (node_isset(nodeid, mem_nodes_parsed)) {
+		if (node_isset(nodeid, numa_nodes_parsed)) {
 			pr_info("Node %d already present, skipping\n",
 				nodeid);
 			continue;
@@ -167,11 +167,10 @@
 
 		prevbase = base;
 		numa_add_memblk(nodeid, base, limit);
-		node_set(nodeid, mem_nodes_parsed);
 		node_set(nodeid, numa_nodes_parsed);
 	}
 
-	if (!nodes_weight(mem_nodes_parsed))
+	if (!nodes_weight(numa_nodes_parsed))
 		return -ENOENT;
 
 	/*