Created by: lidanqing-intel

In softmax_mkldnn_op.cc, SoftmaxMKLDNNKernel and SoftmaxMKLDNNGradKernel only currently only NC data format is supported. More format should be supported when necessary.

[removed TODO] // TODO(jczaja): Add layouts support when there is a need to do so // Two dimensional softmax does support NC format