Revert D26007050: add channels last support for thnn_conv2d (non-dilated)
Test Plan: revert-hammer
Differential Revision:
D26007050 (https://github.com/pytorch/pytorch/commit/8b88c246701419b4604f9a31a0e944a601970e8a)
Original commit changeset: 1289e0687c24
fbshipit-source-id: 88b679efbcae572fe604d50e2199861cadbc3d4a
