gpio: tegra186: add Tegra234 PMC compatible in GPIO driver

Using this patch we are adding PMC compatible string for
Tegra234 in GPIO driver so the IRQ hierarchy can be set.

Signed-off-by: Manish Bhardwaj <mbhardwaj@nvidia.com>
Signed-off-by: Prathamesh Shete <pshete@nvidia.com>
Reviewed-by: Linus Walleij <linus.walleij@linaro.org>
Acked-by: Thierry Reding <treding@nvidia.com>
Signed-off-by: Bartosz Golaszewski <bartosz.golaszewski@linaro.org>