xhci: free xhci virtual devices with leaf nodes first

xhci: free xhci virtual devices with leaf nodes first

commit ee8665e28e8d90ce69d4abe5a469c14a8707ae0e upstream.

the tt_info provided by a HS hub might be in use to by a child device
Make sure we free the devices in the correct order.

This is needed in special cases such as when xhci controller is
reset when resuming from hibernate, and all virt_devices are freed.

Also free the virt_devices starting from max slot_id as children
more commonly have higher slot_id than parent.

Reported-by: Guenter Roeck <groeck@chromium.org>
Tested-by: Guenter Roeck <groeck@chromium.org>
Signed-off-by: Mathias Nyman <mathias.nyman@linux.intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>