vfio: Introduce a vfio_uninit_group_dev() API call

This pairs with vfio_init_group_dev() and allows undoing any state that is
stored in the vfio_device unrelated to registration. Add appropriately
placed calls to all the drivers.

The following patch will use this to add pre-registration state for the
device set.

Signed-off-by: Max Gurtovoy <mgurtovoy@nvidia.com>
Reviewed-by: Cornelia Huck <cohuck@redhat.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jason Gunthorpe <jgg@nvidia.com>
Link: https://lore.kernel.org/r/3-v4-9ea22c5e6afb+1adf-vfio_reflck_jgg@nvidia.com
Signed-off-by: Alex Williamson <alex.williamson@redhat.com>
diff --git a/samples/vfio-mdev/mbochs.c b/samples/vfio-mdev/mbochs.c
index 3e885be..0f151184 100644
--- a/samples/vfio-mdev/mbochs.c
+++ b/samples/vfio-mdev/mbochs.c
@@ -559,6 +559,7 @@ static int mbochs_probe(struct mdev_device *mdev)
 	dev_set_drvdata(&mdev->dev, mdev_state);
 	return 0;
 err_mem:
+	vfio_uninit_group_dev(&mdev_state->vdev);
 	kfree(mdev_state->pages);
 	kfree(mdev_state->vconfig);
 	kfree(mdev_state);
@@ -572,6 +573,7 @@ static void mbochs_remove(struct mdev_device *mdev)
 	struct mdev_state *mdev_state = dev_get_drvdata(&mdev->dev);
 
 	vfio_unregister_group_dev(&mdev_state->vdev);
+	vfio_uninit_group_dev(&mdev_state->vdev);
 	atomic_add(mdev_state->type->mbytes, &mbochs_avail_mbytes);
 	kfree(mdev_state->pages);
 	kfree(mdev_state->vconfig);