Deprecate CNNModelHelper - MLP()
Deprecate CNNModelHelper - MLP()

Summary: This diff deprecates `CNNModelHelper` in `MLP()` function.

Reviewed By: harouwu

Differential Revision: D5241738

fbshipit-source-id: 03669a4166a02257aa5779860d06b40d7496104d

xzturn/caffe2,xzturn/caffe2,bwasti/caffe2,caffe2/caffe2,davinwang/caffe2,sf-wind/caffe2,Yangqing/caffe2,Yangqing/caffe2,pietern/caffe2,sf-wind/caffe2,bwasti/caffe2,pietern/caffe2,davinwang/caffe2,Yangqing/caffe2,pietern/caffe2,sf-wind/caffe2,sf-wind/caffe2,xzturn/caffe2,Yangqing/caffe2,Yangqing/caffe2,sf-wind/caffe2,xzturn/caffe2,davinwang/caffe2,pietern/caffe2,bwasti/caffe2,pietern/caffe2,davinwang/caffe2,xzturn/caffe2,bwasti/caffe2,davinwang/caffe2,bwasti/caffe2