Issue 270 fix (#274)

* check if torch.backends has mps before calling it

* Fixes issue 270

Co-authored-by: James Reynolds <magnsuviri@me.com>

scripts/orig_scripts/img2img.py

@@ -200,7 +200,7 @@ def main():
  config = OmegaConf.load(f"{opt.config}")
  model = load_model_from_config(config, f"{opt.ckpt}")
 
- device = choose_torch_device()
+ device = torch.device(choose_torch_device())
  model = model.to(device)
 
  if opt.plms: