Revert D28242069: Add cuSOLVER path for torch.linalg.lstsq
Test Plan: revert-hammer
Differential Revision:
D28242069 (https://github.com/pytorch/pytorch/commit/7b31d4262bc2f8f4d9e6a52795d02190070d2709)
Original commit changeset: 23979d19ccc7
fbshipit-source-id: edf26a78b3485790deb1a8f53e8c8d3989c28e1b
