Revert "usb: host: xhci-plat: Create platform device for onboard hubs in probe()"

This reverts commit c950686b as the
patch series is causing build issues in linux-next at the moment.

Cc: Matthias Kaehlcke <mka@chromium.org>
Link: https://lore.kernel.org/r/YMuRcrE8xlWnFSWW@google.com


Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>