hte: tegra194: improve the GPIO-related comment

Using any of the GPIO interfaces using the global numberspace is
deprecated. Make it clear in the comment.

Signed-off-by: Bartosz Golaszewski <bartosz.golaszewski@linaro.org>
Acked-by: Linus Walleij <linus.walleij@linaro.org>
Reviewed-by: Dipen Patel <dipenp@nvidia.com>
Signed-off-by: Dipen Patel <dipenp@nvidia.com>