Add a pointer to udev in struct xhci_virt_device. When allocate a new
virt_device, make the pointer point to the corresponding udev.

Modify xhci_check_args(), check if virt_dev->udev matches the target udev,
to make sure command is issued to the right device.
Signed-off-by: NAndiry Xu <andiry.xu@amd.com>
Signed-off-by: NSarah Sharp <sarah.a.sharp@linux.intel.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@suse.de>