SpinFast

I'm still looking to work on this at some point this summer and clean it up, but if anyone wishes to continue the work please don't let me stop you!

> I think that's the gist! > > [My imxrt-sai branch](https://github.com/imxrt-rs/imxrt-hal/compare/main...mciantyre:imxrt-hal:imxrt-sai) has Florob's and my suggestions. If it's OK with @SpinFast, I'm happy to apply the fixups and force push...