Update P2-P7 models/hub variants (#6230)

* Update p2-p7 `models/hub` variants

* Update common.py

* AutoAnchor camelcase corrections

models/common.py

@@ -306,7 +306,7 @@ class DetectMultiBackend(nn.Module):
 
         if pt:  # PyTorch
             model = attempt_load(weights if isinstance(weights, list) else w, map_location=device)
-            stride = int(model.stride.max())  # model stride
+            stride = max(int(model.stride.max()), 32)  # model stride
             names = model.module.names if hasattr(model, 'module') else model.names  # get class names
             self.model = model  # explicitly assign for to(), cpu(), cuda(), half()
         elif jit:  # TorchScript