drivers: gpio: davinci: fix config layout

Zephyr GPIO drivers require the pin mask `struct gpio_driver_data` to be
the first element of the driver config. Reordering fixes failures in ASSERT
statements of the GPIO driver due to the base address being interpreted as
supported pin mask.

Signed-off-by: Mika Braunschweig <mika.braunschweig@siemens.com>