Add the warning message for API with linear modules (#28766)
Summary:
Pull Request resolved: https://github.com/pytorch/pytorch/pull/28766
Add the warning message to explicitly ask the users to upgrade the deprecated `torch.jit.quantized` API to the new `torch.quantization.quantize_dynamic` API.
ghstack-source-id: 92711620
Test Plan: CI
Differential Revision: D18164903
fbshipit-source-id: e6aff2527f335c2d9f362e6856ce8597edb52aaa
