pinctrl: tegra: Add suspend and resume support

This patch adds support for Tegra pinctrl driver suspend and resume.

During suspend, context of all pinctrl registers are stored and
on resume they are all restored to have all the pinmux and pad
configuration for normal operation.

Acked-by: Thierry Reding <treding@nvidia.com>
Reviewed-by: Dmitry Osipenko <digetx@gmail.com>
Signed-off-by: Sowjanya Komatineni <skomatineni@nvidia.com>
Link: https://lore.kernel.org/r/1564607463-28802-2-git-send-email-skomatineni@nvidia.com


Signed-off-by: Linus Walleij <linus.walleij@linaro.org>