usb: hub: Support 'set hub depth' request for USB 3.0 hubs

USB 3.0 hub uses a hub depth value multiplied by four as an offset
into the 'route string' to locate the bits it uses to determine the
downstream port number. We shall set the hub depth value of a USB
3.0 hub after it is configured.

Signed-off-by: Bin Meng <bmeng.cn@gmail.com>
Reviewed-by: Simon Glass <sjg@chromium.org>
3 files changed