The xHCI USB hub is connected to an GPIO on the DFI BayTrail SoM. For
correct operation, it needs to get reset upon power-up. Otherwise it
may happen that the hub is not detected after a software reboot. This
patch also configures this GPIO in the dts for correct operation.
Signed-off-by: Stefan Roese <sr@denx.de> Cc: Simon Glass <sjg@chromium.org> Reviewed-by: Bin Meng <bmeng.cn@gmail.com>