[POWERPC] Sky Cpu and Nexus: check for platform_get_resource retcode

Add adds checking for platform_get_resource() return code to prevent
possible NULL pointer usage.

Signed-off-by: Cyrill Gorcunov <gorcunov@gmail.com>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Kumar Gala <galak@gate.crashing.org>
Cc: Brian Waite <waite@skycomputers.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Paul Mackerras <paulus@samba.org>
diff --git a/drivers/misc/hdpuftrs/hdpu_nexus.c b/drivers/misc/hdpuftrs/hdpu_nexus.c
index fda9998..01bc917 100644
--- a/drivers/misc/hdpuftrs/hdpu_nexus.c
+++ b/drivers/misc/hdpuftrs/hdpu_nexus.c
@@ -62,6 +62,11 @@
 	int *nexus_id_addr;
 
 	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+	if (!res) {
+		printk(KERN_ERR "sky_nexus: "
+		       "Invalid memory resource.\n");
+		return -EINVAL;
+	}
 	nexus_id_addr = ioremap(res->start,
 				(unsigned long)(res->end - res->start));
 	if (nexus_id_addr) {
@@ -69,7 +74,7 @@
 		chassis_id = *nexus_id_addr & 0xff;
 		iounmap(nexus_id_addr);
 	} else {
-		printk(KERN_ERR "Could not map slot id\n");
+		printk(KERN_ERR "sky_nexus: Could not map slot id\n");
 	}
 
 	hdpu_slot_id = create_proc_entry("sky_slot_id", 0666, &proc_root);