Fix `get_module()` bug in timm_efficientdet (#842)
Summary:
Fixes https://github.com/pytorch/benchmark/issues/840 and https://github.com/pytorch/benchmark/issues/839
Pull Request resolved: https://github.com/pytorch/benchmark/pull/842
Reviewed By: jansel
Differential Revision: D35273628
Pulled By: xuzhao9
fbshipit-source-id: f0ebba72543b3c7d0f98f6e67627c480052468ab
