hisi_acc_vfio_pci: bugfix the problem of uninstalling driver

In a live migration scenario. If the number of VFs at the
destination is greater than the source, the recovery operation
will fail and qemu will not be able to complete the process and
exit after shutting down the device FD.

This will cause the driver to be unable to be unloaded normally due
to abnormal reference counting of the live migration driver caused
by the abnormal closing operation of fd.

Therefore, make sure the migration file descriptor references are
always released when the device is closed.

Fixes: b0eed085 ("hisi_acc_vfio_pci: Add support for VFIO live migration")
Signed-off-by: Longfang Liu <liulongfang@huawei.com>
Reviewed-by: Shameer Kolothum <shameerali.kolothum.thodi@huawei.com>
Link: https://lore.kernel.org/r/20250510081155.55840-5-liulongfang@huawei.com


Signed-off-by: Alex Williamson <alex.williamson@redhat.com>