of: Add NVIDIA Tegra XUSB pad controller binding

This patch adds the device tree binding documentation for the XUSB pad
controller found on NVIDIA Tegra SoCs. It exposes both pinmuxing and PHY
capabilities.

Tested-by: Mikko Perttunen <mperttunen@nvidia.com>
Acked-by: Linus Walleij <linus.walleij@linaro.org>
Signed-off-by: Thierry Reding <treding@nvidia.com>
diff --git a/include/dt-bindings/pinctrl/pinctrl-tegra-xusb.h b/include/dt-bindings/pinctrl/pinctrl-tegra-xusb.h
new file mode 100644
index 0000000..914d56d
--- /dev/null
+++ b/include/dt-bindings/pinctrl/pinctrl-tegra-xusb.h
@@ -0,0 +1,7 @@
+#ifndef _DT_BINDINGS_PINCTRL_TEGRA_XUSB_H
+#define _DT_BINDINGS_PINCTRL_TEGRA_XUSB_H 1
+
+#define TEGRA_XUSB_PADCTL_PCIE 0
+#define TEGRA_XUSB_PADCTL_SATA 1
+
+#endif /* _DT_BINDINGS_PINCTRL_TEGRA_XUSB_H */