Licensing clashes

[hyandell]

Hi AXLearn folk,

Looking at the source, I noticed that there is both LGPL-3.0 and Non-Commercial content, both of which would seem to clash with the project's intended license of Apache-2.0.

LGPL-3.0: https://github.com/apple/axlearn/blob/main/axlearn/vision/fpn.py
CC-NC: https://github.com/apple/axlearn/blob/main/axlearn/common/splade_test.py

Flagging for your review.