Removed unused weight update in prepack. Moved zero point update to (#32254)
Summary:
qlinear/qconv to be consistent with data update.
Pull Request resolved: https://github.com/pytorch/pytorch/pull/32254
Differential Revision: D19422929
Pulled By: kimishpatel
fbshipit-source-id: 595a4f7d6fde4978c94f3e720ec8645f3f2bdb7a
