gpio: tegra: tegra_gpio_config shouldn't be __init

This function is called from non-__init context, just like
tegra_gpio_enable()/disable(). Remove the __init annotation to avoid
section mismatch warnings during compile.

Signed-off-by: Stephen Warren <swarren@wwwdotorg.org>
Signed-off-by: Grant Likely <grant.likely@secretlab.ca>