[PATCH] Handle empty nodes in sysfs on x86-64

This code is shared between i386 and x86-64, and x86-64 needs to check
for empty nodes here.  Otherwise you can get oopses at boot in some
circumstances. 

This handles empty nodes != 0; empty node zero are still broken in other
ways.

include/asm-i386/cpu.h

@@ -17,7 +17,11 @@ static inline int arch_register_cpu(int num){
 	struct node *parent = NULL;
 	
 #ifdef CONFIG_NUMA
-	parent = &node_devices[cpu_to_node(num)].node;
+	int node = cpu_to_node(num);
+
+	if (!node_online(node))
+		return 0; 
+	parent = &node_devices[node].node;
 #endif /* CONFIG_NUMA */
 
 	return register_cpu(&cpu_devices[num].cpu, num, parent);