vduse: Cleanup the old kernel states after reset failure

We should cleanup the old kernel states e.g. interrupt callback
no matter whether the userspace handle the reset correctly or not
since virtio-vdpa can't handle the reset failure now.

Otherwise, the old state might be used after reset which might
break something, e.g. the old interrupt callback might be triggered
by userspace after reset, which can break the virtio device driver.

Signed-off-by: Xie Yongji <xieyongji@bytedance.com>
Link: https://lore.kernel.org/r/20210906142158.181-1-xieyongji@bytedance.com


Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Acked-by: Jason Wang <jasowang@redhat.com>