* cherry-pick:add softmax_switch for softmax_with_cross_entropy_op, test=develop

* add softmax_switch for softmax_with_cross_entropy_op, test=develop

* delete using EigenMatrix in softmax_with_cross_entropy_op.h, test=develop

* add REGISTER_OP_VERSION for softmax_switch attr of softmax_with_cross_entropy_op, test=develop

* cherry-pick:add softmax_switch for softmax_with_cross_entropy_op,test=develop

* change softmax_switch to use_softmax, test=develop

* fix code format for softmax_with_cross_entropy_op.cc, test=develop