Add mobilenetv2 as backbone model.

[zeynepozdemir]

I added the mobilenetv2 model defined in mmclassification as a backboned model. The forward function of the model here returns a tuple value as you can see in the attachment. When I run it with Prototypical Networks, I get the attached error on line 46.

Eror:

When I use the Resnet12 model defined in mmfewshot, support_feads and query_feads appear as attached. How can I make MobileNetV2 compatible?