YOLOv5 Apple Metal Performance Shader (MPS) support (#7878)

* Apple Metal Performance Shader (MPS) device support

Following https://pytorch.org/blog/introducing-accelerated-pytorch-training-on-mac/

Should work with Apple M1 devices with PyTorch nightly installed with command `--device mps`. Usage examples:
```bash
python train.py --device mps
python detect.py --device mps
python val.py --device mps
```

* Update device strategy to fix MPS issue

models/tf.py

@@ -536,7 +536,7 @@ def run(
 ):
     # PyTorch model
     im = torch.zeros((batch_size, 3, *imgsz))  # BCHW image
-    model = attempt_load(weights, map_location=torch.device('cpu'), inplace=True, fuse=False)
+    model = attempt_load(weights, device=torch.device('cpu'), inplace=True, fuse=False)
     _ = model(im)  # inference
     model.info()