gpio: tegra186: Program interrupt route mapping

The controls for the GG port on Tegra194 resides in the power partition
of the C5 PCIe controller and its interrupt route mapping can therefore
not be programmed by early boot firmware along with that of the other
ports.

Detect this generically by looking at which controls have already been
locked down using the security registers and fill in default values for
controls that are unlocked.

Signed-off-by: Thierry Reding <treding@nvidia.com>
Signed-off-by: Bartosz Golaszewski <bgolaszewski@baylibre.com>