[Examples] Make sure EMA works with any device (#2382)

* Fix EMA

* up

* update

examples/text_to_image/train_text_to_image.py

@@ -438,6 +438,7 @@ def main():
             if args.use_ema:
                 load_model = EMAModel.from_pretrained(os.path.join(input_dir, "unet_ema"), UNet2DConditionModel)
                 ema_unet.load_state_dict(load_model.state_dict())
+                ema_unet.to(accelerator.device)
                 del load_model
 
             for i in range(len(models)):