stm32 i2cv1 async regression, silently reads back 0xFF

[MabezDev]

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Will need to do a bisect to find the offending commit, but essentially somewhere between the crates.io release and current main there is a regression where i2c doesn't fail it just reads back 0xFF. This was produced on an F2 board, but it more than likely applies to other chips with i2cv1.

Blocking of course works fine.