Remove TH/THC link for cholesky_solve (#15691)
Summary:
Changelog:
- Remove TH/THC binding
- Port single matrix case to ATen
Pull Request resolved: https://github.com/pytorch/pytorch/pull/15691
Differential Revision: D13579317
Pulled By: soumith
fbshipit-source-id: 63a55606c656396e777e8e6828acd2ef88ed1543
