[PyTorch] MHA: remove TODO about transposing second arg to linear() (#72229)
Summary:
Pull Request resolved: https://github.com/pytorch/pytorch/pull/72229
linear() transposes its second argument internally.
ghstack-source-id: 148259782
Test Plan: CI, review
Reviewed By: zrphercule
Differential Revision: D33962112
fbshipit-source-id: fedb2139d652ab933f9a0829db6060d14e3e3c7a
(cherry picked from commit 2b4259db0b62bcfca089352fb6d76d100616d2d2)
