NMS MPS device wrapper (#9620)

* NMS MPS device wrapper

May resolve https://github.com/ultralytics/yolov5/issues/9613

Signed-off-by: Glenn Jocher <glenn.jocher@ultralytics.com>

* Update general.py

Signed-off-by: Glenn Jocher <glenn.jocher@ultralytics.com>

Signed-off-by: Glenn Jocher <glenn.jocher@ultralytics.com>

utils/general.py

@@ -843,7 +843,9 @@ def non_max_suppression(
     if isinstance(prediction, (list, tuple)):  # YOLOv5 model in validation model, output = (inference_out, loss_out)
         prediction = prediction[0]  # select only inference output
 
-    if 'mps' in prediction.device.type:  # MPS not fully supported yet, convert tensors to CPU before NMS
+    device = prediction.device
+    mps = 'mps' in device.type  # Apple MPS
+    if mps:  # MPS not fully supported yet, convert tensors to CPU before NMS
         prediction = prediction.cpu()
     bs = prediction.shape[0]  # batch size
     nc = prediction.shape[2] - nm - 5  # number of classes
@@ -930,6 +932,8 @@ def non_max_suppression(
                 i = i[iou.sum(1) > 1]  # require redundancy
 
         output[xi] = x[i]
+        if mps:
+            output[xi] = output[xi].to(device)
         if (time.time() - t) > time_limit:
             LOGGER.warning(f'WARNING ⚠️ NMS time limit {time_limit:.3f}s exceeded')
             break  # time limit exceeded