ARM: Tegra: Harmony: Add USB device

The Tegra USB port is attached an an SMSC9514; a combination USB hub
and Ethernet controller.

This change is extracted from a change in the ChromeOS 2.6.38 kernel.

Signed-off-by: Olof Johansson <olofj@chromium.org>
Signed-off-by: Stephen Warren <swarren@nvidia.com>
Signed-off-by: Olof Johansson <olof@lixom.net>