iris: refcount separate screen objects for resource tracking

iris: refcount separate screen objects for resource tracking

this screen object can never, ever be accessed like this in a resource,
as it may have previously been replaced by a wrapper (e.g., driver trace)
which will then explode when it is accessed directly

instead, keep a separate screen ref on the resource which is known to be
the actual driver object and not a wrapper

Fixes: 0a497eb1303 ("iris: make resources take a ref on the screen object")

Reviewed-by: Lionel Landwerlin lionel.g.landwerlin@intel.com
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/10632>