NNAPI: add flexible size support for conv2d (#57561)
Summary:
Pull Request resolved: https://github.com/pytorch/pytorch/pull/57561
Add flexible size support for conv2d op in nnapi model conversion
Test Plan:
pytest test/test_nnapi.py
Imported from OSS
Reviewed By: dreiss
Differential Revision: D28200848
fbshipit-source-id: d94ccf48a3d8453aa8e96c7cac02948c4cd870cc
