sony-laptop: Ignore missing _DIS method on pic device

At least the Vaio VGN-Z540N doesn't have this method, so let's not fail
to suspend just because it doesn't exist.
Signed-off-by: Adam Jackson <ajax@redhat.com>
Acked-by: Mattia Dongili <malattia@linux.it>
Signed-off-by: Len Brown <len.brown@intel.com>

drivers/misc/sony-laptop.c

@@ -2315,8 +2315,10 @@ end:
  */
 static int sony_pic_disable(struct acpi_device *device)
 {
-	if (ACPI_FAILURE(acpi_evaluate_object(device->handle,
-			"_DIS", NULL, NULL)))
+	acpi_status ret = acpi_evaluate_object(device->handle, "_DIS", NULL,
+					       NULL);
+
+	if (ACPI_FAILURE(ret) && ret != AE_NOT_FOUND)
 		return -ENXIO;
 
 	dprintk("Device disabled\n");