Fixed use_accel not defined issue (#1363)

Author: BLOrange-AMD

imagenet/main.py

@@ -459,7 +459,7 @@ def update(self, val, n=1):
         self.avg = self.sum / self.count
 
     def all_reduce(self):    
-        if use_accel:
+        if self.use_accel:
             device = torch.accelerator.current_accelerator()
         else:
             device = torch.device("cpu")