[nnpi fake ops] bug fix int8QuantizeNNPI (#39271)
Summary:
Pull Request resolved: https://github.com/pytorch/pytorch/pull/39271
Caused 10% NE loss. Bug in emulation itself and NNPI is fine.
Test Plan: mobile_cvr has no NE loss after this fix: https://fburl.com/mlhub/z6hd8rhn
Reviewed By: hyuen
Differential Revision: D21793205
fbshipit-source-id: a908e95c26c2353f982d05e0a20f02f3c724715d
