[RFC PATCH v2 02/13] hwspinlock: add callback to fill private data of a hwspinlock

[Wolfram Sang]

>    Don't you break the existing users of this API with this change? I see
> you're fixing them up in the followup patches but that's not how it should
> be done -- the compilation shouldn't be broken...

I am not breaking them. The helper is an additional feature and the old
way still works until patch 8. Until then, all users are converted.

I built tested it :)