x86/PCI: default pcibus cpumask to all cpus if it lacks affinity

The early initialization of the pci bus to node mapping leaves all busses
with a node id of -1 if it lacks memory affinity.  Thus, cpumask_of_pcibus
must return all online cpus for such busses.
Signed-off-by: David Rientjes <rientjes@google.com>
Signed-off-by: Jesse Barnes <jbarnes@virtuousgeek.org>

arch/x86/include/asm/pci.h

@@ -143,7 +143,11 @@ static inline int __pcibus_to_node(const struct pci_bus *bus)
 static inline const struct cpumask *
 cpumask_of_pcibus(const struct pci_bus *bus)
 {
-	return cpumask_of_node(__pcibus_to_node(bus));
+	int node;
+
+	node = __pcibus_to_node(bus);
+	return (node == -1) ? cpu_online_mask :
+			      cpumask_of_node(node);
 }
 #endif