Migrate `eig` from the TH to Aten (CUDA) (#44105)
Summary:
Fixes https://github.com/pytorch/pytorch/issues/24553
Pull Request resolved: https://github.com/pytorch/pytorch/pull/44105
Reviewed By: heitorschueroff
Differential Revision: D24853669
Pulled By: mruberry
fbshipit-source-id: a513242dc7f49f55dbc6046c18d8a9d9aa2aaf8d
