pinctrl: tegra: Make PINCTRL_TEGRA select PINMUX && PINCONF

Then we can remove "select PINMUX && PINCONF" from PINCTRL_TEGRA{20,30}.
This simplifies the dependency.

Signed-off-by: Axel Lin <axel.lin@ingics.com>
Acked-by: Stephen Warren <swarren@nvidia.com>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>