MIPS: cpumask_of_node() should handle -1 as a node

pcibus_to_node can return -1 if we cannot determine which node a pci bus
is on. If passed -1, cpumask_of_node will negatively index the lookup array
and pull in random data:

# cat /sys/devices/pci0000:00/0000:00:01.0/local_cpus
00000000,00000003,00000000,00000000
# cat /sys/devices/pci0000:00/0000:00:01.0/local_cpulist
64-65

Change cpumask_of_node to check for -1 and return cpu_all_mask in this
case:

# cat /sys/devices/pci0000:00/0000:00:01.0/local_cpus
ffffffff,ffffffff,ffffffff,ffffffff
# cat /sys/devices/pci0000:00/0000:00:01.0/local_cpulist
0-127
Signed-off-by: Anton Blanchard <anton@samba.org>
Cc: linux-mips@linux-mips.org
Cc: linux-kernel@vger.kernel.org
Cc: Rusty Russell <rusty@rustcorp.com.au>
Cc: Andrew Morton <akpm@linux-foundation.org>
Patchwork: http://patchwork.linux-mips.org/patch/831/Signed-off-by: Ralf Baechle <ralf@linux-mips.org>

arch/mips/include/asm/mach-ip27/topology.h

@@ -24,7 +24,9 @@ extern struct cpuinfo_ip27 sn_cpu_info[NR_CPUS];
 
 #define cpu_to_node(cpu)	(sn_cpu_info[(cpu)].p_nodeid)
 #define parent_node(node)	(node)
-#define cpumask_of_node(node)	(&hub_data(node)->h_cpus)
+#define cpumask_of_node(node)	((node) == -1 ?				\
+				 cpu_all_mask :				\
+				 &hub_data(node)->h_cpus)
 struct pci_bus;
 extern int pcibus_to_node(struct pci_bus *);