vfio/ccw: move private to mdev lifecycle

vfio/ccw: move private to mdev lifecycle

Now that the mdev parent data is split out into its own struct,
it is safe to move the remaining private data to follow the
mdev probe/remove lifecycle. The mdev parent data will remain
where it is, and follow the subchannel and the css driver
interfaces.

Signed-off-by: Eric Farman <farman@linux.ibm.com>
Reviewed-by: Matthew Rosato <mjrosato@linux.ibm.com>
Link: https://lore.kernel.org/r/20221104142007.1314999-5-farman@linux.ibm.com
Signed-off-by: Alex Williamson <alex.williamson@redhat.com>