[SCSI] pm8001:fix potential NULL pointer dereference

Signed-off-by: Jack Wang <jack_wang@usish.com>
Signed-off-by: James Bottomley <James.Bottomley@suse.de>
diff --git a/drivers/scsi/pm8001/pm8001_sas.c b/drivers/scsi/pm8001/pm8001_sas.c
index 49721c8..487f78f 100644
--- a/drivers/scsi/pm8001/pm8001_sas.c
+++ b/drivers/scsi/pm8001/pm8001_sas.c
@@ -616,11 +616,11 @@
 	spin_lock_irqsave(&pm8001_ha->lock, flags);
 
 	pm8001_device = pm8001_alloc_dev(pm8001_ha);
-	pm8001_device->sas_device = dev;
 	if (!pm8001_device) {
 		res = -1;
 		goto found_out;
 	}
+	pm8001_device->sas_device = dev;
 	dev->lldd_dev = pm8001_device;
 	pm8001_device->dev_type = dev->dev_type;
 	pm8001_device->dcompletion = &completion;