Revert D31445799: [nnc] Use given kernel function name while emitting code
Test Plan: revert-hammer
Differential Revision:
D31445799 (https://github.com/pytorch/pytorch/commit/c30dc52739c083d8b10f36ed3e84f765f349fe9b)
Original commit changeset: 8d1642098313
fbshipit-source-id: 6b9d8c816437e9fcba8eb19cc683bc0a46a04cf5
