Add a new driver for the XUSB pad controller found on NVIDIA Tegra SoCs. This hardware block used to be exposed as a pin controller, but it turns out that this isn't a good fit. The new driver and DT binding much more accurately describe the hardware and are more flexible in supporting new SoC generations. Acked-by: Kishon Vijay Abraham I <[email protected]> Signed-off-by: Thierry Reding <[email protected]>