usb: misc: fix improper handling of refcount in uss720_probe()

usb: misc: fix improper handling of refcount in uss720_probe()

usb_put_dev shouldn't be called when uss720_probe succeeds because of
priv->usbdev. At the same time, priv->usbdev shouldn't be set to NULL
before destroy_priv in uss720_disconnect because usb_put_dev is in
destroy_priv.

Fix this by moving priv->usbdev = NULL after usb_put_dev.

Fixes: dcb4b8ad6a44 ("misc/uss720: fix memory leak in uss720_probe")
Cc: stable <stable@kernel.org>
Reviewed-by: Dongliang Mu <mudongliangabcd@gmail.com>
Signed-off-by: Hangyu Hua <hbh25y@gmail.com>
Link: https://lore.kernel.org/r/20220407024001.11761-1-hbh25y@gmail.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>