arch/powerpc/platforms/powernv/opal-elog.c: fix world-writable sysfs files

If you don't have a store function, you're not writable anyway!
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
Acked-by: Stewart Smith <stewart@linux.vnet.ibm.com>

arch/powerpc/platforms/powernv/opal-elog.c

@@ -82,9 +82,9 @@ static ssize_t elog_ack_store(struct elog_obj *elog_obj,
 }
 
 static struct elog_attribute id_attribute =
-	__ATTR(id, 0666, elog_id_show, NULL);
+	__ATTR(id, S_IRUGO, elog_id_show, NULL);
 static struct elog_attribute type_attribute =
-	__ATTR(type, 0666, elog_type_show, NULL);
+	__ATTR(type, S_IRUGO, elog_type_show, NULL);
 static struct elog_attribute ack_attribute =
 	__ATTR(acknowledge, 0660, elog_ack_show, elog_ack_store);