[PATCH 11/13] vfio/mdev: consolidate all the available_instance sysfs into the core code

[Tian, Kevin]

> From: Tian, Kevin
> Sent: Tuesday, June 14, 2022 6:14 PM
> 
> > From: Christoph Hellwig
> > Sent: Tuesday, June 14, 2022 12:54 PM
> >
> > Every driver just print a number, simply add a method to the mdev_driver
> > to return it and provide a standard sysfs show function.
> 
> I didn't get why not simply adding a field to mdev_type?

Please ignore this comment. It's a dumb fact that available instances
is dynamic especially when shared resources may exist between
different types which cannot be generalized in the core.

Reviewed-by: Kevin Tian <kevin.tian at intel.com>