[NNAPI] Fix hardtanh (#47520)
Summary:
Pull Request resolved: https://github.com/pytorch/pytorch/pull/47520
NNAPI defines "RELU1" as clamping from [-1, 1], not [0, 1] as I
previously assumed. Fix our implementation to match.
Test Plan: Upcoming unit test.
Reviewed By: axitkhurana
Differential Revision: D25317934
Pulled By: dreiss
fbshipit-source-id: 70efd5bb6092b0628ff6b765ce6f6274ef28d741
