powerpc: some changes in numa_setup_cpu()

this patches changes some error handling logics in numa_setup_cpu(),
when cpu node is not found, so:

if the cpu is possible, but not present, -1 is kept in numa_cpu_lookup_table,
so later, if the cpu is added, we could set correct numa information for it.

if the cpu is present, then we set the first online node to
numa_cpu_lookup_table instead of 0 ( in case 0 might not be an online node? )

Cc: Nishanth Aravamudan <nacc@linux.vnet.ibm.com>
Cc: Nathan Fontenot <nfont@linux.vnet.ibm.com>
Signed-off-by: Li Zhong <zhong@linux.vnet.ibm.com>
Acked-by: Nishanth Aravamudan <nacc@linux.vnet.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>

arch/powerpc/mm/numa.c

@@ -538,7 +538,7 @@ static int of_drconf_to_nid_single(struct of_drconf_cell *drmem,
  */
 static int numa_setup_cpu(unsigned long lcpu)
 {
-	int nid;
+	int nid = -1;
 	struct device_node *cpu;
 
 	/*
@@ -555,19 +555,21 @@ static int numa_setup_cpu(unsigned long lcpu)
 
 	if (!cpu) {
 		WARN_ON(1);
-		nid = 0;
-		goto out;
+		if (cpu_present(lcpu))
+			goto out_present;
+		else
+			goto out;
 	}
 
 	nid = of_node_to_nid_single(cpu);
 
+out_present:
 	if (nid < 0 || !node_online(nid))
 		nid = first_online_node;
-out:
-	map_cpu_to_node(lcpu, nid);
 
+	map_cpu_to_node(lcpu, nid);
 	of_node_put(cpu);
-
+out:
 	return nid;
 }