improve how pytorch_android cmake imports static lib (#26525)
Summary:
Pull Request resolved: https://github.com/pytorch/pytorch/pull/26525
Create a util function to avoid boilerplate code as we are adding more
libraries.
Test Plan: - build CI;
Differential Revision: D17495394
Pulled By: ljk53
fbshipit-source-id: 9e19f96ede4867bdff5157424fa68b71e6cff8bf
