pinctrl: add a driver for NVIDIA Tegra

This adds a driver for the Tegra pinmux, and required parameterization
data for Tegra20 and Tegra30.

The driver is initially added with driver name and device tree compatible
value that won't cause this driver to be used. A later change will switch
the pinctrl driver to use the correct values, switch the old pinmux
driver to be disabled, and update all code that uses the old pinmux APIs
to use the new pinctrl APIs.

Signed-off-by: Stephen Warren <swarren@nvidia.com>
Acked-by: Olof Johansson <olof@lixom.net>
[squashed "fix case of Tegra30's foo_groups[] arrays"]
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>