make sparse coalesce warp size aware (#25918)
Summary:
Use the new C10_WARP_SIZE macro to make the sparse coalesce kernel warp size aware.
Pull Request resolved: https://github.com/pytorch/pytorch/pull/25918
Differential Revision: D17286442
Pulled By: bddppq
fbshipit-source-id: a079f012c32e5786b49b2a6973019d847ee11897
