This patch adds UDC driver for tegra XUSB 3.0 device mode controller.
XUSB device mode controller supports SS, HS and FS modes

Based on work by:
  Mark Kuo <mkuo@nvidia.com>
  Hui Fu <hfu@nvidia.com>
  Andrew Bresticker <abrestic@chromium.org>
Signed-off-by: Nagarjuna Kristam <nkristam@nvidia.com>
Acked-by: Thierry Reding <treding@nvidia.com>
Signed-off-by: Felipe Balbi <felipe.balbi@linux.intel.com>