Support is_mtia attribute. (#108307) (#108310)
Summary:
FBGEMM uses `self.iter.is_cuda` to check if the tensor is for CUDA. This diff enables similar feature `self.iter.is_mtia` for tensors with MTIA device key.
Test Plan: See diff D48693225
Reviewed By: jackm321
Differential Revision: D48809191
Pull Request resolved: https://github.com/pytorch/pytorch/pull/108310
Approved by: https://github.com/albanD
