Update base for Update on "allow customized head_dim"

This is for resolving the ask in this [post](https://fb.workplace.com/groups/pytorch.edge.users/permalink/1574875706716050/).

Similar change in HF: huggingface/transformers#32502

Differential Revision: [D65974454](https://our.internmc.facebook.com/intern/diff/D65974454/)

[ghstack-poisoned]

Author: helunwencser