Revert "Adding multiweight support for shufflenetv2 prototype models"

This reverts commit 31fadbe.

Author: jdsgomes

torchvision/prototype/models/__init__.py

@@ -5,7 +5,6 @@
 from .efficientnet import *
 from .mobilenetv3 import *
 from .mnasnet import *
-from .shufflenetv2 import *
 from . import detection
 from . import quantization
 from . import segmentation