gpio: tegra: Fix offset of pinctrl calls

This patch hunk is a lightly modified version of a diff found
in a Tegra code dump from a product tree. It makes a lot of
sense because this is what most drivers do.

Cc: Thierry Reding <treding@nvidia.com>
Cc: Stefan Agner <stefan@agner.ch>
Cc: Dmitry Osipenko <digetx@gmail.com>
Cc: Jon Hunter <jonathanh@nvidia.com>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>