soc/tegra: Select pinctrl for Tegra194

Select PINCTRL_TEGRA194 by default for Tegra194 SoC needed for
dynamically controlling PCIe pins.

Signed-off-by: Krishna Yarlagadda <kyarlagadda@nvidia.com>
Reviewed-by: Linus Walleij <linus.walleij@linaro.org>
Signed-off-by: Thierry Reding <treding@nvidia.com>