gpio: tps68470: Make tps68470_gpio_output() always set the initial value

Make tps68470_gpio_output() call tps68470_gpio_set() for output-only pins
too, so that the initial value passed to gpiod_direction_output() is
honored for these pins too.

Fixes: 275b13a6

 ("gpio: Add support for TPS68470 GPIOs")
Reviewed-by: Andy Shevchenko <andy.shevchenko@gmail.com>
Reviewed-by: Daniel Scally <dan.scally@ideasonboard.com>
Tested-by: Daniel Scally <dan.scally@ideasonboard.com>
Reviewed-by: Sakari Ailus <sakari.ailus@linux.intel.com>
Signed-off-by: Hans de Goede <hdegoede@redhat.com>
Signed-off-by: Bartosz Golaszewski <bartosz.golaszewski@linaro.org>